Ingredients
For the Chocolate Cake
1/2 cup granulated sugar
2 tablespoons light brown sugar, tightly packed
1/2 cup sour cream
1/3 cup vegetable oil
1 large egg, at room temperature
1 teaspoon vanilla extract
1/4 teaspoon salt
3/4 cup all-purpose flour
1/3 cup cocoa powder
1/2 teaspoon baking soda
For the Mocha Buttercream Frosting
1.5 ounces unsweetened chocolate, finely chopped
1 tablespoon instant coffee or espresso powder
2 sticks (1 cup) unsalted butter, at room temperature
2 cups confectioner’s sugar
1 cup mini chocolate chips
Instructions
For the Chocolate Cake
Preheat the oven to 350 (F) and place your oven rack in the center position.
Prepare two 6-inch round cake pans by spraying liberally with non-stick cooking spray and line the bottoms of each cake pan with parchment paper. Spray the parchment paper.
In a large bowl, whisk together 1/2 cup granulated sugar, 2 tablespoons light brown sugar, 1/2 cup sour cream, 1/3 cup vegetable oil, 1 large egg, 1 teaspoon vanilla extract and 1/4 teaspoon salt until well combined.
Add 3/4 cup all-purpose flour, 1/3 cup cocoa powder and 1/2 teaspoon baking soda and continue whisking until the batter is smooth and the dry ingredients have just been incorporated into the wet ingredients.
Be careful not to overmix or your cake will be dense and I will cry for you; it’s okay to have one or two small flour streaks left in the batter.
Transfer the batter into your prepared cake pans and bake until just firm, around 20 to 22 minutes.
When the cakes are ready, a skewer inserted into the center of each cake should come out clean and the tops should bounce back when gently poked with a finger.
Once the cakes are finished baking, transfer the pans to a wire rack to cool for 15 minutes, before inverting the cakes out of the pans to cool completely before frosting.
For the Mocha Buttercream Frosting
In a large, heatproof metal bowl, combine 1.5 ounces finely chopped bittersweet chocolate and 1 tablespoon instant coffee or espresso powder.
Place the heatproof metal bowl over a saucepan filled with water, making sure that the water does not touch the bottom of the bowl. Melt the chocolate by bringing the water to a boil and constantly stirring the chocolate with a whisk.
Once the chocolate is completely melted, whisk in 2 sticks unsalted butter and 2 cups confectioner’s sugar, whisking until combined and the mixture has lightened to a pale brown. If too soft to spread, chill the frosting until spreadable, whisking occasionally. If not, use immediately.
Place 1 cup of the frosting on top of one cake, using an icing spatula to create an even layer. Sprinkle 1 cup mini chocolate chips on top of the frosting, before nestling the second cake on top of the chocolate chips. Use the remainder of the frosting to frost the cake completely.
