This easy chocolate orange cake is bursting with citrus and dark chocolate flavor. It's a simple single layer of moist chocolate cake made with fresh orange juice, orange zest and buttermilk.
The cake is topped with swirls of quick chocolate orange ganache and dried orange slices. Orange and chocolate pair here to create a rich and vibrant cake.

I was inspired to make this recipe after making a chocolate orange cheesecake this winter. Rather than a more complex layer cake (like this triple chocolate cake), I opted for a simple, single layer that would be easy to put together without much fuss.
I adapted my recipe for chocolate olive oil bundt cake in order to make the cake layer even more dark and moist with a rich and fudgy consistency. Black cocoa powder adds a deeper chocolate flavor and dramatic black color. A generous amount of orange zest and orange juice provide maximum citrus punch.
The result is a single layer cake with a bright citrus flavor and incredibly moist, fudgy chocolate taste. It's blanketed with an easy chocolate ganache made with sour cream, dark chocolate and even more citrus zest. Chocolate dipped dried citrus wheels provide the perfect cake decoration.
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Ingredients
* See recipe card for detailed list of ingredients and quantities.
FOR THE CAKE
Dutch process cocoa powder - This recipe specifically calls for Dutch process cocoa powder for its dark color and extra chocolate flavor. Do not replace with natural cocoa.
Black cocoa powder - Black cocoa powder has been heavily alkalized, making it into an "extra Dutch process" cocoa. This results in a deep black color and a flavor much like an Oreo cookie.
Vegetable oil - Feel free to use any neutral vegetable oil here, such as grapeseed, avocado or canola oil.
Eggs - Large eggs should be at room temperature.
Buttermilk - The acid in buttermilk helps break down gluten in baked goods, providing a more tender crumb. Its signature tang also pairs well with orange.
Orange zest - The zest of a large navel orange adds a punch of fresh citrus flavor.
Espresso powder - Instant espresso powder enhances the chocolate flavor without providing a noticeable coffee taste.
Orange juice - Freshly squeezed orange juice is best here - you'll need about 3 medium to large oranges for this amount.
FOR THE EASY GANACHE
Sour cream - Use full fat sour cream for richness. This is a great way to make chocolate ganache with no cream!
Orange zest - After grating, chop the zest very finely so that it doesn't create a noticeable texture in the frosting.
Dark chocolate - I use a chocolate bar with 72% cocoa. Feel free to select any bar with 50-72% chocolate according to your preference. I wouldn't go any darker than that.
FOR THE DECORATION
Make dried orange slices dipped in dark chocolate and place onto the frosted cake.
Instructions
Step 1: Combine all dry ingredients together in a medium bowl: flour, cocoa powders, salt, and baking powder. Set aside.
Step 2: In a large mixing bowl, whisk together vegetable oil, sugar and eggs.
Step 3: Add buttermilk, orange zest, vanilla extract and espresso powder. Whisk together.
Step 4: Add ⅓ of dry ingredients. Whisk to combine. Add half of orange juice.
Step 5: Alternate adding remaining dry ingredients and orange juice, ending with dry ingredients. Whisk until fully combined. Pour into prepared pan.
Step 6: Bake for 40-45 minutes at 350 degrees Fahrenheit (177° Celsius, Gas mark 4). Remove and cool in pan for 10 minutes, then turn out onto baking rack to fully cool.
Hint: This is a very moist and fudgy cake. When you test it for doneness, there should still be some wet crumbs (but not gooey batter) on the toothpick. I recommend you test at the 40 minute mark as oven temperatures vary!
For the ganache:
Step 1: Add sour cream to a large mixing bowl. Add finely chopped orange zest and whisk to combine. Set aside while you melt chocolate.
Step 2: In a microwave safe bowl, melt chopped chocolate in 30 second bursts, stirring after each.
Step 3: Add melted chocolate to sour cream mixture, whisking gently to combine. Scrape sides and bottom of bowl with a spatula to ensure chocolate is fully incorporated.
Scoop ganache onto cake and spread to edges using a swirling motion with a mini offset spatula or the back of a spoon.
Substitutions
Black cocoa powder - I like to use part black cocoa powder in the cake as it adds dramatic color and an extra depth of flavor to the cake.
If you can't source it, feel free to replace it with an equal amount of Dutch process cocoa powder.
Sour cream - You can substitute an equal amount of full fat Greek yogurt or crème fraîche in the ganache in place of the sour cream.
Equipment
8 inch round pan - This 8 x 3 inch heavy duty aluminum cake pan is great quality.
A small offset spatula makes it easy to spread the chocolate ganache. It's an indispensable tool for frosting cakes and cookies and spreading batters into pans.
Storage
Keep the cake at room temperature for 2-3 hours. After that, store in an airtight container in the refrigerator for up to 3 days (due to the sour cream in the frosting). Bring to room temperature before serving.
To freeze, wrap in plastic wrap and place in an airtight container in the freezer for up to 2 months. Defrost in the refrigerator, then bring to room temperature before serving.
Recipe Tips
Make sure the cake is fully cooled before adding the chocolate ganache.
Add the ganache soon after mixing it up. It will thicken and eventually set up as it cools. In order to swirl it over the cake easily, spread it on while still soft.
If the ganache thickens too much before you add it to the cake, simply warm it in a metal or ceramic bowl over a small pan filled with hot water. Stir frequently until the consistency becomes thinner and more spreadable.
Love this recipe? Please leave a comment and star rating. ★★★★★ Your feedback, suggestions, and adaptations are very helpful to other bakers!
📖 Recipe
Chocolate Orange Cake
INGREDIENTS
Chocolate Orange Cake
- 150 grams (1¼ cups) all purpose flour
- 52 grams (½ cup) cocoa powder, Dutch process
- 32 grams (¼ cup) black cocoa powder
- ½ teaspoon kosher salt
- 1½ teaspoons baking powder
- 83 mL (⅓ cup) vegetable oil
- 200 grams (1 cup) granulated sugar
- 2 large eggs
- 187 mL (¾ cup) buttermilk
- orange zest , from 1 navel orange
- 1½ teaspoons vanilla extract
- 2 teaspoons espresso powder, instant
- 187 mL (¾ cup) orange juice, freshly squeezed
Chocolate orange ganache
- 240 grams (1 cup) sour cream, full fat
- orange zest, from 1 navel orange
- 200 grams (7 ounces) dark chocolate, finely chopped
Dried orange decoration
- dried orange slices, (click for recipe)
INSTRUCTIONS
Chocolate orange cake
- Preheat oven to 350 degrees Fahrenheit (177° Celsius, Gas mark 4). Place rack in center of oven.
- Line the base of an 8 inch x 3 inch cake pan with parchment paper. Grease the sides. Set aside.
- In a medium bowl, whisk together flour, cocoa powders, salt and baking powder. Set aside.150 grams (1¼ cups) all purpose flour, 52 grams (½ cup) cocoa powder, 32 grams (¼ cup) black cocoa powder, ½ teaspoon kosher salt, 1½ teaspoons baking powder
- In a large mixing bowl, whisk together oil and granulated sugar. Add eggs one at a time, beating well between additions.83 mL (⅓ cup) vegetable oil, 200 grams (1 cup) granulated sugar, 2 large eggs
- Add buttermilk, orange zest, vanilla extract and espresso powder. Whisk well to combine all wet ingredients.187 mL (¾ cup) buttermilk, orange zest, 1½ teaspoons vanilla extract, 2 teaspoons espresso powder
- Add ⅓ of dry ingredients, whisking thoroughly. Add ½ of orange juice and mix well.187 mL (¾ cup) orange juice
- Alternate adding remaining dry ingredients and orange juice, ending with dry. Whisk until fully blended. Pour into prepared pan.
- Bake for 40-45 minutes, until top springs back when touched and a toothpick comes out with just a few wet crumbs attached (but not gooey batter.) Do not overbake! Cool in pan for 10 minutes and then flip out onto a baking rack to finish cooling.
Chocolate orange ganache
- Add sour cream to a large mixing bowl. Add finely chopped orange zest and whisk to combine. Set aside while you melt chocolate.240 grams (1 cup) sour cream, orange zest
- In a microwave safe bowl, melt chopped chocolate in 30 second bursts, stirring after each.200 grams (7 ounces) dark chocolate
- Add melted chocolate to sour cream mixture, whisking gently to combine. Scrape sides and bottom of bowl with a spatula to ensure chocolate is fully incorporated. Scoop ganache onto cake and spread to edges using a swirling motion with a mini offset spatula or the back of a spoon.
Notes
- I like to use part black cocoa powder in the cake as it adds dramatic color and an extra depth of flavor. If you can't source it, feel free to replace it with an equal amount of Dutch process cocoa powder.
- This is a very moist and fudgy cake. When you test for doneness, there should still be some wet crumbs (but not gooey batter) on the toothpick. I recommend you test at the 40 minute mark as oven temperatures vary!
- Make sure the cake is fully cooled before adding chocolate ganache.
- Add the ganache soon after mixing it up. The ganache will thicken and eventually set up as it cools. In order to swirl it over the cake easily, spread it on while still soft.
- If the ganache thickens too much before you add it to the cake, warm it in a metal or ceramic bowl over a small pan filled with hot water. Stir frequently until the consistency becomes thinner and more spreadable.
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