chocolate, coffee, and banana might seem like a weird flavor combination, but think about what you grab on your way out the door in the morning. probably a banana and a cup of coffee, right? this is just an elevated version of that.
the cake itself is identical in flavor to banana bread, but much lighter in texture. any dryness is dispelled thanks to a coffee-cream soak, then the layers get covered with a smooth mocha buttercream and rich chocolate espresso ganache. i also added chocolate-covered espresso beans for crunch. feel free to decorate the top like i did, with a border that looks like frilly tits.
cake (adapted from the momofuku milk bar cookbook)
- 6 tbsp butter, room temperature
- 1 cup sugar
- 1 egg, room temperature
- 1/2 cup buttermilk
- 2 tbsp grapeseed or canola oil
- 1/2 tsp vanilla extract
- 2 ripe bananas (the browner the better)
- 1 1/3 cups flour
- 3/4 tsp baking powder
- 1/2 tsp baking soda
- 1/2 tsp kosher salt
mocha buttercream (adapted from brown eyed baker)
- 1 cup (2 sticks) butter, room temperature
- 3 cups powdered sugar
- 2 tbsp cocoa powder (optional)
- 1 1/2 tsp instant espresso powder
- 1 1/2 tsp vanilla extract
chocolate espresso ganache
- 8 oz semisweet chocolate, chopped
- 8 oz heavy cream
- 2 tbsp instant espresso powder
- 1/4 cup heavy cream
- 1/4 cup strong coffee
- chocolate-covered espresso beans
- gold sprinkles, dragées
for the cake, preheat the oven to 350º. grease a quarter sheet pan and line with parchment paper. cream together the butter and sugar in a stand mixer on medium speed for 3 minutes. scrape down the bowl. stream in the buttermilk, oil, and vanilla, then beat for 5 to 6 minutes, until mixture is fluffy and white. on low speed, add the bananas, then the dry ingredients. stir just until combined. spread the batter evenly in the pan and bake for 20-25 minutes. cool in the pan for 10 minutes, then remove to a rack and cool completely.
for the mocha buttercream, dissolve the espresso powder in the vanilla extract in a small bowl. beat the butter, powdered sugar, and cocoa powder in a stand mixer for 3-5 minutes, until fluffy. add the espresso mixture and beat for another 2 minutes.
for the ganache, put the chocolate and espresso powder in a heatproof bowl. heat the cream in a small saucepan (or the microwave) until almost boiling. remove from heat and pour over the chocolate. let sit for 5 minutes, then stir until completely smooth. let sit at room temperature until thickened.
for the soak, stir together the coffee and cream.
to assemble, use the cake ring to punch two circles and two half circles out of the cake. reserve scraps for snacking. wipe off the cake ring, then place it on a sheet pan. lay a 6-inch circle of cardboard (or cake board) in the bottom. line the ring with the strip of acetate. place the two half circles in the bottom, adding scraps if needed to complete the circle. brush with the soak. use the back of a spoon to spread on some buttercream. spread on half of the ganache (heat briefly in the microwave before using if it set too hard). sprinkle on lots of espresso beans. repeat with the second layer, using a whole round. nestle the final layer on top. cover the top of the cake with buttercream, and smooth it out as much as possible. transfer the sheet pan to the freezer, and freeze for at least 12 hours (or up to 2 weeks). when ready to serve, remove the ring and acetate and pipe a border with remaining frosting, if desired (i used a french tip). add gold details.