This blackberry poppy seed cake is a celebration of late summer flavors, particularly blackberry and basil, which are growing in abundance in my garden (the basil, thankfully) and neighborhood at this time of year. This cake recipe features an easy, moist cake packed full of poppy seeds, with alternating layers of vibrant purple blackberry basil jam and a lightly sweetened mascarpone cream frosting. I've dressed it up with a delicate caramel sauce drip and a fruit crown of late summer bounty.
I've been wanting to make a jam filled cake recipe like this ever since seeing a scroll-stopping cross section of a similar cake on Instagram from the delight inducing Seattle cake shop, Deep Sea Sugar & Salt. Their version used a black currant blackberry jam and cream cheese frosting, but I had a vat of mascarpone in the fridge again, and a small forest of basil growing in our raised garden beds out front. I went over the top and added a caramel sauce drip and some seasonal late summer fruit as decoration. I loved the visual drama of deep purple blackberries, figs, and blueberries, and thought it played well with the golden glow of the caramel sauce.
The glorious combination of sweet, acidic blackberries and creamy mascarpone is one I discovered a few summers ago. I put together a honey blackberry mascarpone ice cream during my race to use up another 5 pound container of mascarpone cheese. I also made this chocolate coffee mascarpone tart, and this lemon mascarpone ice cream with a red currant swirl. If you need something quick and easy, there's also grilled peaches with honey and mascarpone.
And for other cake recipes with jam, there's my brown sugar cake with rhubarb compote and creme fraiche buttercream, and this pineapple jam that would make a wonderful cake filling!
The poppy seed cake is my adaptation of a well loved poppy seed loaf cake published in the NY Times. It's filled to the brim with poppy seeds soaked in warm milk to tenderize their tough outer shell and release extra flavor. It's delicate, moist and has a slightly nutty flavor and fun textural crunch that is a nice foil for the creamy mascarpone.
The blackberry basil jam is an easy recipe that pairs two classic summer flavors into a deliciously sweet and sharp combination. The spicy flavor of Genovese Basil tempers the jam's sweetness and keeps it all from being cloying.
And there's the mascarpone, a delightfully adaptable ingredient with a wide range of uses that can swing either sweet or savory. Here I've used it in a lightly sweetened mascarpone cream frosting to which I've added a bit of vanilla and almond extract. Whipped with heavy cream, it thickens beautifully, creating the delight sometimes known as chantilly mascarpone. Mascarpone icing is wonderfully easy to spread on the cake layers, pipe as a dam to keep the jam from escaping, and cover the cake's exterior with a minimal naked look.
I dripped a whisper thin layer of caramel sauce over the cake to add a golden touch and nice notes of deeply toasted sugar. The fresh fruit piled atop the cake echoes the notes of late summer present in the flavors, and provides a simple, minimal decoration. Bonus - edible cake decorations!
FOR THE POPPY SEED CAKE
Poppy Seeds - Yes, this is a significant amount of poppy seeds! The recipe calls for 100 grams (¾ cup). which is the amount you see reflected in the photos here. You are welcome to reduce the amount by half if the texture is too seedy for you. I recommend sourcing poppy seeds in bulk, as they are much more affordable than the small jars in the grocery store. For the cake, soak the poppy seeds in hot milk to soften their outer coating and help release additional flavor when baked.
Whole milk - you can substitute with milk alternatives here if desired. The milk is warmed to soak the poppy seeds.
All purpose flour provides structure in the cake.
Baking powder - for leavening the cake and adding volume. With no strong acid in the ingredients, baking powder provides both the base and acid needed for the cake to rise.
Kosher salt - for added flavor.
Unsalted butter - using unsalted butter allows you to control the total quantity of salt in the recipe. Salt contentin salted butter varies from brand to brand. The butter should be cubed and at room temperature.
Granulated sugar - for sweetness, tenderness, and moisture.
Eggs - as a binder to provide structure to the cake, as well as adding fat and flavor.
Vanilla extract, almond extract, and lemon zest add flavor and compliment the poppy seeds.
FOR THE BLACKBERRY BASIL JAM
Fresh blackberries - You can substitute frozen blackberries here if needed. Just thaw them fully before cooking.
Fresh basil leaves - I have Genovese basil, also known as sweet basil, growing in my garden. I picked enough leaves to measure ½ ounce, which is ¾ cup of loosely packed leaves. You must use fresh leaves in this recipe. Do not substitute with dried basil. Other basil varieties will work as well. They'll each impart their own unique flavor.
Lemon juice - lemon juice improves the taste and lowers the pH of the jam. This helps the pectin set as it is released from the cooked and sweetened fruit. Using either fresh or bottled lemon juice is fine for this purpose.
Granulated sugar - Sugar sweetens the jam and helps the natural pectin to set. This is a fairly low sugar jam, so I don't recommend reducing the amount any further.
For a good reference regarding when your jam is finished cooking, refer to this post on ensuring your jam sets. This blackberry jam can be kept, well sealed, in the refrigerator for up to a month. Please consult an expert source on canning and food preservation if you wish to can this (or any) jam.
FOR THE MASCARPONE CREAM FROSTING
Mascarpone cheese - The mascarpone provides the main flavor in this frosting recipe. It's important that it be used chilled here, directly from the fridge. Here in the US, you can usually source an 8 ounce tub of mascarpone in the cheese section of the dairy aisle at your local grocery store. If you can't find mascarpone, you might substitute the creme fraiche buttercream frosting from this cake recipe instead.
Heavy whipping cream - Also needs to be chilled, directly from the fridge.
Powdered sugar - Powdered sugar provides sweetness and a bit of thickening power.
Vanilla extract and almond extract, for a boost in flavor.
FOR THE CARAMEL SAUCE
Granulated sugar and water are heated in a heavy saucepan until fully dissolved and golden brown in color. They form the base of the caramel sauce.
Heavy whipping cream - Cream provides the rich, smooth texture to the caramel sauce. Warming the cream before adding it to the hot sugar mixture will help reduce the possibility that the sugar will seize.
Unsalted butter - For extra richness and smooth mouthfeel.
Vanilla extract and Kosher salt, for flavor.
Blackberry liqueur - A few teaspoons of blackberry liqueur (crème de mûre) is an optional addition. It provides a subtle hit of blackberry to the caramel sauce. You could also add crème de cassis, which is made from blackcurrants.
Frequently Asked Questions
Mascarpone (pronounced mahs-car-POHN-ay) is a soft, spreadable Italian cheese made from heavy cream. It is thickened with either citric or tartaric acid. It's well known for being a key ingredient in the traditional Italian dessert, tiramisu.
It is most comparable to British clotted cream, or creme fraiche, although its texture is somewhat thicker and falls somewhere between creme fraiche and American cream cheese. Mascarpone has a rich flavor due to its butterfat content of 60-75%. Cream cheese, which is made with milk and cream, has a butterfat content of around 33%.
Mascarpone adds a rich and creamy element to both sweet and savory recipes, ranging from a topping on pizza to the filling of a fruit pavlova.
Yes! You can certainly use your own preferred jam for cake filling. You'll probably need about 1 cup of jam for the filling. I do really think you should try this recipe for blackberry jam with basil, though! It has amazing flavor and is quite easy to put together. It's one of the standout parts of the cake for me.
This berry mascarpone cake is made up of three 6 inch cakes that are torted (divided in half horizontally) into a total of 6 layers. Each layer ends up having a smooth, exterior side and an exposed, crumb filled interior side. To minimize crumbs in the frosting and make spreading the mascarpone cream easier, add each cake layer with the exposed crumb side down.
Since the frosting includes a fair amount of heavy cream and mascarpone, I recommend storing the cake in the refrigerator if it's not going to be served within an hour or two. Allow enough time for the cake to come to room temperature before serving, however! The flavor and texture of a cake made with butter, such as this one, is always best at room temperature.
Blackberry Poppy Seed Layer CakePrint Recipe Pin Recipe
POPPY SEED LAYER CAKE
- 100 grams (¾ cup) poppy seeds
- 250 mL (1 cup) whole milk
- 240 grams (2 cups) all purpose flour
- 2 ½ teaspoons baking powder
- ½ teaspoon kosher salt
- 226 grams (1 cup, 8 ounces) unsalted butter, room temperature, cubed
- 200 grams (1 cup) granulated sugar
- 3 large eggs, room temperature
- 2 teaspoons vanilla extract
- ½ teaspoon almond extract
- lemon zest (from 1 medium lemon)
BLACKBERRY BASIL JAM
- 525 grams (3 cups) fresh blackberries
- 14 grams (½ ounce, ¾ cups loosely packed) fresh basil leaves
- 1 Tablespoon lemon juice, freshly squeezed
- 100 grams (½ cup) granulated sugar
MASCARPONE CREAM FROSTING
- 226 grams (8 ounces, 1 cup) mascarpone cheese, chilled
- 2 teaspoons vanilla extract
- ¼ teaspoon almond extract
- 220 grams (1 cup) powdered sugar, sifted
- 250 mL (1 cup) heavy whipping cream, chilled
- 200 grams (1 cup) granulated sugar
- 60 mL (¼ cup) water
- 125 mL (½ cup) heavy whipping cream, warm
- 28 grams (2 Tablespoons) unsalted butter
- 1 teaspoon vanilla extract
- ½ teaspoon kosher salt
- 2 teaspoons blackberry liqueur, such as creme de mure (optional)
LATE SUMMER FRUITS FOR DECORATION
- Seasonal fruit such as pears, figs, plums, blackberries and blueberries.
- Basil leaves and other floral additions as appropriate (make sure they are edible and/or food safe!)
POPPY SEED LAYER CAKE
- Preheat oven to 350° Fahrenheit (177° Celsius, Gas Mark 4)
- Grease three 6” cake pans and cut circles of parchment paper to place in the bottom of each pan.
- In a 1 quart saucepan, warm the milk and poppy seeds over medium heat until the mixture comes to a boil. Remove from heat and set aside to cool.250 mL (1 cup) whole milk, 100 grams (¾ cup) poppy seeds
- In a medium bowl, blend the flour, baking powder and salt with a whisk. Set aside.240 grams (2 cups) all purpose flour, 2 ½ teaspoons baking powder, ½ teaspoon kosher salt
- Into the bowl of a stand mixer fitted with the paddle attachment, add the butter and granulated sugar. Mix until light and fluffy. Add the eggs one at a time and mix well between each addition. Scrape down the sides of the bowl. Add the vanilla and almond extracts, and the lemon zest. Mix until incorporated.226 grams (1 cup, 8 ounces) unsalted butter, room temperature, cubed, 200 grams (1 cup) granulated sugar, 3 large eggs, room temperature, 2 teaspoons vanilla extract, ½ teaspoon almond extract, lemon zest (from 1 medium lemon)
- Add half of the flour mixture to the bowl and beat until just combined. Add the poppy seed and milk mixture and beat until smooth. Add the remainder of the flour and mix well. Scrape the bowl with a spatula to ensure there is no unmixed flour at the bottom.
- Pour the cake batter evenly between the three pans. I use my kitchen scale to ensure that the layers are similar in weight.
- Bake for 23-25 minutes, until cake begins to pull away from sides of pan and a toothpick inserted into the center comes out with no crumbs.
- Cool in pans for 10 minutes and then flip onto a metal cooling rack and remove the parchment paper. Cool completely before torting the layers.
- To torte the layers, divide each cake layer into two thinner rounds by slicing carefully in half horizontally with a sharp serrated knife. This will result in 6 cake layers.
BLACKBERRY BASIL JAM
- Yield: 1.5 cups (375 mL) blackberry basil jam, enough to use between cake layers with some extra to spare.
- Place half of the blackberries in a fine mesh strainer over a bowl. Press berries thoroughly to extract as much juice as possible. Be thorough and patient with this step - you'll be surprised how much juice you will get if you work at it for a while. Discard the strained blackberry seeds.525 grams (3 cups) fresh blackberries
- Place the strained blackberry liquid into a blender with the basil leaves and lemon juice. Blend until smooth.14 grams (½ ounce, ¾ cups loosely packed) fresh basil leaves, 1 Tablespoon lemon juice, freshly squeezed
- Into a 3 quart saucepan place the remainder of the blackberries and the sugar. Using a potato masher or the back of a spoon, mash until the berries release their juices and have become saucy. Add the blended blackberry basil mixture and mix well. Cook over medium heat, stirring from time to time to keep the foam down, until mixture has gelled and thickened to a jam-like consistency. Cook time varies depending on your berries, stove temperature, etc. It should take around 20-25 minutes. To test, place a teaspoon of jam into the freezer on a chilled plate - if it remains thick and the juices don't run when tilted, it's ready. Set aside to cool. If making ahead, transfer into lidded mason jars and store in the fridge for up to a month.100 grams (½ cup) granulated sugar
MASCARPONE CREAM FROSTING
- Yield - 3 cups, enough for a thin application between each of the 6 torted cake layers, as a dam for the blackberry basil jam, and to coat the exterior of the cake in a naked cake style.
- In the bowl of a stand mixer fitted with the whisk attachment, combine the chilled mascarpone, vanilla extract, almond extract and powdered sugar. Beat on medium speed until mixed. Scrape down the sides of the bowl. Increase speed to high and beat for 1 minute or so, until light and fluffy. Be careful not to mix too much, as mascarpone is sensitive and can turn grainy when overmixed.226 grams (8 ounces, 1 cup) mascarpone cheese, chilled, 2 teaspoons vanilla extract, ¼ teaspoon almond extract, 220 grams (1 cup) powdered sugar, sifted
- Turn the mixer to high and stream in the heavy whipping cream. Beat for another minute or two, until the mixture is thick and fluffy and can stand up on its own. It should have the consistency of stiff shaving cream. If it's at all runny, whip further. Stop once you've achieved a thick consistency (again, overmixing cream mascarpone can cause graininess and a curdled texture.)250 mL (1 cup) heavy whipping cream, chilled
- Yield - about 2 cups of caramel sauce. I find it's easier to make in this quantity than in smaller batches (it lasts a good long while in the fridge). Feel free to reduce - you'll only need about a quarter this much for the caramel drip.
- In a large, heavy shallow saucepan, add the sugar and water. Cook over medium heat, without stirring, until the color of the sugar mixture is a light copper brown. Quickly remove from heat. Whisking constantly, slowly pour the heavy cream into the hot sugar mixture - be careful as it might sizzle and foam at the beginning.200 grams (1 cup) granulated sugar, 60 mL (¼ cup) water, 125 mL (½ cup) heavy whipping cream, warm
- Continue to whisk until the cream is completely incorporated and the sauce is smooth. Add the butter, vanilla and salt. Stir until butter is melted and mixed in. If including, now whisk in the the blackberry liqueur. Set aside to cool.28 grams (2 Tablespoons) unsalted butter, 1 teaspoon vanilla extract, ½ teaspoon kosher salt, 2 teaspoons blackberry liqueur, such as creme de mure (optional)
- Extra portions can be placed in an airtight container in the refrigerator.
- Place the first of the six torted cake layers onto a serving platter, cut side down. Spread a layer of mascarpone frosting onto the entire layer. Using a piping bag with a large round open tip* (I used a Wilton 1A tip), pipe a circle of frosting around the outside border of the cake, closing it completely. This will create a barrier to prevent the jam from leaking out the sides. Using a spoon, fill the center with jam. There will be three total layers of jam, so portion accordingly. You may have some leftover.* Other alternatives include a piping bag with a simple cut opening or a heavy ziploc bag with a corner cut off.
- Cover with the 2nd layer of cake, cut side down. Press down gently and check the level with each addition. Add a layer of mascarpone, but do not pipe a dam or add jam. Cover with the 3rd layer of cake, cut side down. Repeat the mascarpone, piped border, and jam. Cover with the 4th layer of cake, cut side down. Add another layer of mascarpone, but do not pipe a dam or add jam. Cover with the 5th layer of cake, cut side down. Repeat the mascarpone, piped border, and jam. Cover with the 6th and final layer of cake, cut side down.
- Using an offset spatula and a bench scraper, cover top and sides of cake with the remaining mascarpone frosting. To achieve the naked look, apply a thinner amount and use a bench scraper or cake spatula to expose a bit of the cake underneath. If you have a cake turntable or a lazy suzan you can place the platter on, it will make this process much easier.
- Refrigerate for 30 minutes minimum before adding caramel drip. Test the consistency of your caramel drip by doing a practice run on an upside down quart mason jar or similar container. Your caramel should be at room temperature. If too warm, it will run down the sides too quickly and puddle at the bottom of your cake. Chilling the cake will help control the drip.
- To add the caramel drip, pour enough caramel onto the cake to cover the top. Using a mini offset spatula, gently push a bit of the caramel over the edge in a sweeping motion, following the curve of the cake. This should create a waterfall effect that will push the caramel over the edge into drips. Add additional caramel where needed to create extra drip. Chill cake for an additional 30 minutes to help caramel set before adding fruit decoration.
- For fruit decoration, add the larger fruits first, and then layer in the smaller bits as you go. I chose to form the fruit into a crescent shape. To keep the pear upright, I placed a toothpick halfway into the cake and poked the pear into it. I used a red pear, a green fig cut in two, some purple figs, a few very small Italian plums, blackberries, and blueberries. I also added purple basil and a beautiful purple Japanese maple leaf. Have fun with the decoration!Seasonal fruit such as pears, figs, plums, blackberries and blueberries., Basil leaves and other floral additions as appropriate (make sure they are edible and/or food safe!)
Made this recipe?
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