This snack cake combines coast-to-coast double chocolate cake influences from two stellar bakeries—Miett e in San Francisco and Baked in New York City—and the sour cream ganache frosting comes from Joy of Cooking.
Note that when you’re baking with eggs from backyard chickens, you may need to adjust due to their inconsistent sizes. In baking, large eggs are considered 2 ounces. I’ve built this recipe for high altitude, but it’ll work at the beach if you bump up baking powder to 1¼ teaspoons, baking soda to ¾ teaspoon, and lower the oven temperature to 350°F.
Makes one 8-inch-square cake, about 9 servings
2 ounces bittersweet chocolate (64–70%), chopped
1 cup boiling water
1½ cups all-purpose flour (Wheat Montana)
1 cup dark cocoa powder (Valrhona)
1 teaspoon baking powder
½ teaspoon baking soda
¾ teaspoon kosher salt
2 large eggs
½ cup neutral vegetable oil (I recommend high-oleic safflower oil from The Oil Barn)
1½ cups granulated sugar
1 teaspoon vanilla extract
1 cup butt ermilk
Preheat oven to 375°F. Spray an 8-inch square baking pan with baking spray (or use butter) and dust with cocoa powder. Put chopped bitt ersweet chocolate in a small bowl and pour boiling water over the chocolate; set aside to melt and cool, stirring with a spatula now and then to combine.
Sift together the flour, cocoa powder, baking powder, and baking soda, then sprinkle in the salt.
In a separate bowl using an electric mixer, mix the eggs for a minute or two, then add the oil and mix for another minute. With mixer running on medium speed, add the sugar in a gradual stream and mix for a couple more minutes. Add the vanilla.
Add the buttermilk to the cooled chocolate and stir to combine. Reduce mixer speed to low, then add the cooled chocolate and milk alternately with the sifted dry ingredients—in about three cycles—mixing just until incorporated.
Pour the batter into the prepared pan and bake for 55–60 minutes, or until the center feels baked and springs back with a light finger touch. Let the cake cool in the pan on a rack.
Sour Cream Ganache Frosting
4 ounces bittersweet chocolate (64–70%), chopped
½ cup sour cream, room temperature
Bring a pan of water filled about 1-inch deep to barely a simmer. Turn heat to low and place a metal bowl in the pan to create a double boiler. Melt the chocolate in the metal bowl.
Remove from heat and let cool a few minutes. Whisk in the room-temperature sour cream. Use immediately. If frosting becomes too firm, set the bowl over simmering water until it softens a little, then stir to combine.