Ingredients
Method
- Preheat oven to 350°F. Butter two 8-inch round cake pans, line with parchment, and butter the parchment.
- Sift flour, cocoa, baking soda, and baking powder into a large bowl. Add sugar and salt and whisk to combine.
- Add buttermilk, oil, eggs, and vanilla. Beat with an electric mixer on medium for 2 minutes, scrape bowl, then beat 1 minute more.
- With the mixer on low, slowly pour in the hot coffee. Batter will be thin.
- Divide batter evenly between pans and bake until a toothpick comes out with moist crumbs, 30 to 35 minutes.
- Cool layers in pans on a rack for 10 minutes, then turn out onto the rack to cool completely.
- Melt chocolate over simmering water, then cool until just warm. Beat butter until fluffy, then beat in egg yolk and vanilla. On low, add confectioners' sugar. Stir the dissolved espresso into the melted chocolate, then beat chocolate into the butter mixture until glossy.
- Place one cake layer on a plate, spread 1 cup frosting on top. Top with the second layer and frost the top and sides. Slice and serve.
Notes
Room temperature buttermilk and eggs are not optional for a smooth batter; pull them from the fridge an hour before you start. If your frosting gets too soft while you work, pop the bowl in the refrigerator for 10 minutes and give it a quick re-whip.
