This recipe was inspired by a marzipan filled dark chocolate truffle. Here it is, reinvented as a layer cake. It satisfies all those same notes that the truffle hit: sweet, nutty, floral, chocolatey. The sweet marzipan flavor balances perfectly when paired with a dark chocolate Swiss meringue buttercream.
Add half of the reserved flour mixture, mixing until just incorporated. Remove bowl from mixer.
Fold in the sour cream and the remaining flour.
½ cup sour cream
Pour the cake batter evenly between the four pans. I use my kitchen scale to ensure that the layers are similar in weight.
Bake until a toothpick comes out clean when you pierce the center of the cake, about 30-35 minutes. Cool in pans for 10 minutes and then flip onto a metal cooling rack and remove parchment paper.
DARK CHOCOLATE SWISS MERINGUE BUTTERCREAM
Melt dark chocolate in a microwave safe bowl for one minute. Stir, and then continue microwaving and stirring in 20 second intervals until fully melted. Set aside to cool.
10 ounces (1 ⅔ cups) dark chocolate
Place the egg whites, brown sugar, and cream of tartar into a pot on the stove over medium low heat. Stirring constantly, warm to a temperature of approximately 160 degrees Fahrenheit, or until sugar has dissolved completely.
5 large egg whites, ¼ teaspoon cream of tartar, 1⅓ cups brown sugar
Remove pot from stove and strain through a fine metal sieve into the bowl of a stand mixer.
Beat egg white and sugar mixture on high speed with whisk attachment until glossy, stiff, pillowy meringue peaks form and bowl is cool to the touch - this will most likely take 5 to 10 minutes.
Swap out the whisk attachment for the paddle on your stand mixer. On medium speed, begin adding the butter a few squares at a time, beating until fully incorporated. Continue with this process until all butter has been added. If the buttercream seems to curdle or turn soupy, just keep beating! This is common with ingredients of different temperatures and should right itself if you're patient.
1¾ cups (14 ounces) unsalted butter
Add vanilla extract and melted chocolate, and beat until completely blended together. Scrape the bowl several times to make sure the chocolate is entirely incorporated into the buttercream.
2 teaspoons vanilla extract
CAKE ASSEMBLY
Divide remaining almond paste in half and roll into balls. Using the bottom of a 6" cake pan, trace a circle onto parchment paper. Roll each ball out between two layers of parchment paper to size of circle. Transfer to freezer to chill.Use your fingers or a knife to press or push the almond paste into the circular shape so that you can use all of the almond paste.
170 grams (6 ounces) almond paste
Place the first layer of marzipan cake onto serving platter. Place one 6" almond paste circle on top. Spread with a generous portion of chocolate buttercream using an offset spatula or a knife.
Place second layer of marzipan cake on top of the buttercream. Spread with another portion of chocolate buttercream.
Place the third layer of marzipan cake on top of the buttercream. Gently place the remaining circle of almond paste on top Spread with chocolate buttercream.
Add final layer of marzipan cake on top. Using your offset spatula or knife, apply a thin coat of buttercream to the sides of the cake. If you have a bench scraper, use it to smooth the sides and remove excess buttercream as you rotate the turntable.
Add a generous portion of chocolate buttercream to the top of the cake, and smooth it out to meet the sides.
If you like the look of a thinly frosted, semi-naked cake, you can stop here. Alternatively, you can place the cake in the fridge for approximately 20 minutes to firm up the buttercream crumb coat, and then apply the remaining buttercream to the sides and top for a thicker frosting layer, like I did here.
CHOCOLATE GANACHE DRIP
To apply the chocolate ganache drip to your frosted cake, chill the cake for at least 30 minutes. Meanwhile, heat the cream in a microwave safe dish for approximately 30 seconds or until steaming and just beginning to form bubbles around the sides.
¼ cup heavy whipping cream
Place the finely chopped chocolate into a small bowl (so that all the chocolate will be submerged) and pour the cream over the top. Gently whisk until completely smooth.
2 ounces (⅓ cup) dark chocolate
Let the ganache mixture cool for about 5-10 minutes, and then use a spoon to gently drizzle small amounts of the ganache over the edges of the cake to form drips. Once you have the drips as you like them, spoon additional ganache into the center of the cake and spread just to the edges to fill in. I did a half-drip on this cake, only covering a portion - but this makes enough to go around the entire cake with drips and fill in the top.
Notes
Yes, I realize that I've called this a marzipan cake and then proceeded to use almond paste. For my recipe to appear in internet searches, it's best for it to be named marzipan cake. Almond paste cake doesn't have the same ring, does it?
This recipe is sweet enough with almond paste and doesn't need the additional powdered sugar and corn starch that marzipan requires.
I've provided the link for my homemade almond paste recipe. It's so much fresher and more flavorful than store bought. I highly recommend it! You'll need a full recipe divided between the cake and filling.
If you prefer to purchase almond paste, you'll need 13 ounces/368 grams total, which is basically two store-bought 7 ounce tubes. Use the extra ounce in the filling layers so it doesn't go to waste.
I adapted this recipe from a marzipan layer cake posted on Kitchn by Emily Petrick.
If you prefer, you can make this cake as a two layer 8" cake. Your baking time may need to be adjusted slightly to accommodate the different sized pans. Start checking the cake at 30 minutes and every 5 minutes thereafter.
I came up with this buttercream recipe after studying several others, including one by Stella Parks on Serious Eats and another from Joe Pastry, who I wish was still blogging.
It's very important with Swiss meringue buttercream that your butter be at room temperature. It should be soft to the touch. Cutting the butter into small squares will hasten the warming process somewhat.