½ cup plus 1 tablespoon Dutch-process cocoa powder
½ cup plus 1 tablespoon hot water
2¼ cups all-purpose flour
¾ tsp. baking soda
¾ tsp. baking powder
½ tsp. salt
2 sticks plus 1 tablespoon unsalted butter, at room temperature
1 2/3 cups sugar
3 large eggs, at room temperature
1 tbsp. vanilla extract
¾ cup sour cream
step 1: Show Images
Preheat the oven to 350˚ F. Line cupcake pans with paper liners. In a small bowl, combine the cocoa powder and hot water and whisk until smooth. In another medium bowl combine the flour, baking soda, baking powder, and salt, and whisk to blend.
step 2: Show Images
Combine the butter and sugar in a medium saucepan set over medium heat. Cook, stirring occasionally, until the mixture is smooth and the butter is completely melted. Transfer the mixture to the bowl of an electric mixer and beat on medium-low speed until the mixture is cool, about 4-5 minutes. Add the eggs one at a time, mixing well after each addition and scraping down the sides of the bowl as needed. Blend in the vanilla and then the cocoa mixture until smooth. With the mixer on low speed, add the flour mixture in three additions alternating with the sour cream, beginning and ending with the dry ingredients and mixing each addition just until incorporated.
step 3: Show Images
Divide the batter evenly between the prepared liners. Bake until a toothpick inserted in the center comes out clean, about 18-20 minutes, rotating the pans halfway through baking. Let cool in the pan about 5-10 minutes, then transfer to a wire rack to cool completely.