
2 14- or 15-ounce cans (see note)
1/4 cup plus 2 tablespoons all-purpose flour, plus more for dusting
3 tablespoons buttermilk
Yolk of 1 egg
1/2 teaspoon vanilla
3 tablespoons unsalted butter, melted and cooled
2 tablespoons unsweetened cocoa
1/8 teaspoon baking soda
1/8 teaspoon salt
1/3 cup granulated sugar
6 ounces milk chocolate, finely chopped (about 1 cup)
3 ounces bittersweet or semisweet chocolate, finely chopped (about 1/2 cup)
1/4 cup plus 3 tablespoons sour cream, at room temperature
1/2 teaspoon vanilla
Pinch of salt
Birthday candles or edible decorations
Preheat oven to 325 degrees. Grease the inside of the cans and lightly dust with flour, tapping out excess. Place cans on baking sheet and set aside. Combine the buttermilk, egg yolk and vanilla in a small bowl and whisk to mix. Gradually pour the butter into the mixture, whisking constantly.
In a medium bowl, whisk together the remaining 1/4 cup and 2 tablespoons flour, the cocoa, baking soda, salt and sugar until well-blended. Add the buttermilk mixture and whisk until dry ingredients are just moistened. Divide the batter between the two cans; they will be one-quarter to one-third full. Bake until a toothpick inserted comes out clean, 25 to 30 minutes. Transfer cans to a wire rack for 15 minutes. Run a thin knife around the edge of each can and invert to release the cakes. Turn cakes upright and cool before frosting.
In the top of a double boiler over low heat, combine both chocolates, stirring until they melt. Let mixture cool for 5 minutes, then add sour cream, vanilla and salt, and whisk until well-blended. Let cool to room temperature, stirring occasionally. When cool, it should be thick enough to spread. If not, refrigerate for several minutes to thicken. To frost: Cut each cake in half horizontally. Spread a 1/2-inch layer of frosting on the cut side of one cake half, then stack the other half on top. Frost the top and sides of both cakes. Garnish with candles or edible decorations.
By Debby Maugans Nakos