Ingredients
Method
Step-by-Step
- Heat the oven to 350°F (175°C). Grease a 9-inch round cake pan, line the bottom with parchment, and lightly flour the sides.
- Whisk the flour, sugar, cocoa powder, baking powder, baking soda, and salt in a large bowl until evenly combined.
- In a second bowl, whisk the egg, buttermilk, oil, and vanilla until smooth. Pour the wet mixture into the dry ingredients and stir just until no dry streaks remain.
- Slowly pour in the hot coffee or water while whisking gently. The batter will be thin, which is exactly what creates a moist cake.
- Pour the batter into the prepared pan. Bake for 23 to 27 minutes, or until the center springs back lightly and a toothpick inserted in the middle shows a few moist crumbs.
- Cool the cake in the pan for 10 minutes, then transfer it to a wire rack. Let it cool completely before frosting.
- For the frosting, beat the softened butter and cocoa powder until smooth. Add the powdered sugar, milk or cream, vanilla, and salt, then beat until fluffy and spreadable.
- Spread the frosting over the cooled cake. Slice with a warm, clean knife and serve.
Notes
Do not overmix the batter, and measure flour by spooning it into a cup and leveling the top. Store the frosted cake covered at room temperature for up to 2 days or in the refrigerator for up to 5 days. Let chilled slices sit at room temperature for 20 minutes before serving.