Ingredients
3 tablespoons sugar
4 1/2 teaspoons instant coffee granules
4 1/2 teaspoons unsweetened Dutch-process cocoa powder
1/2 cup (1 stick) unsalted butter, softened, plus more for pan
2 cups all-purpose flour, plus more for pan
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon salt
1 cup sugar
2 large eggs, room temperature
1 cup sour cream, room temperature
1 teaspoon pure vanilla extract
Preparation
Preheat oven to 350 degrees. Make the filling: Stir together sugar, coffee, and cocoa powder in a small bowl; set aside.
Butter a 10-inch (12-cup) Bundt pan. Dust with flour, and tap out excess. Make the batter: Whisk flour, baking powder, baking soda, and salt in a medium bowl. Put butter and sugar into the bowl of an electric mixer fitted with the paddle attachment. Mix on medium-high speed until pale and fluffy, 3 to 4 minutes. Reduce speed to medium. Mix in eggs, one at a time. Mix in flour mixture in 3 batches, alternating with sour cream. Add vanilla, and mix 1 minute.
Spread 1/3 of the batter into prepared pan. Sprinkle with half the filling. Spread another third of the batter on top, followed by the remaining filling. Spread remaining batter over top. Run a thin knife through batter to marbleize.
Bake until a cake tester inserted into center comes out clean, 35 to 38 minutes. Let cool 30 minutes. Invert onto a plate.
