For this recipe, we used 3/4-cup paper baking molds for panettone (by Novacart; $0.25 each; surlatable.com).
1 1/2 cups sugar
1 cup buttermilk
1/2 cup brewed coffee, cooled
3/4 cup vegetable oil
2 large eggs, at room temperature
1/2 teaspoon salt
1 teaspoon vanilla extract
2 cups flour
About 1/2 cup unsweetened cocoa powder
1/4 cup espresso powder
2 teaspoons baking soda
1 teaspoon baking powder
6 ounces semisweet chocolate chunks
4 ounces bittersweet chocolate, chopped
1/2 cup whipping cream
Coffee beans for garnish
How to Make It
Preheat oven to 350°. In a bowl with a mixer, beat sugar, buttermilk, coffee, oil, eggs, salt, and vanilla on medium speed until well blended.
Whisk together flour, 1/2 cup cocoa powder, espresso powder, baking soda, and baking powder in a bowl to blend. Gradually add to wet mixture; beat on medium speed until smooth, scraping down sides as necessary. Stir in semisweet chocolate chunks.
Set baking molds on a rimmed baking pan and fill each about two-thirds full. Bake until a toothpick inserted in centers (avoid chocolate chunks) comes out clean, about 27 minutes. Cool cakes completely on a rack.
Melt bittersweet chocolate with cream in a small saucepan over very low heat and stir with a rubber spatula until smooth and blended. Remove from heat and let cool until thick but still spreadable, about 40 minutes. Spread on cakes. Top each cake with a few coffee beans and dust with cocoa. Let frosting firm up completely before serving, at least 30 minutes.