Directions
Preheat the oven to 350 degrees Fahrenheit. Grease two round cake pans with 1 tablespoon of butter and dust them with 1 tablespoon of flour. In a large bowl, whisk together the remaining flour, sugar, cocoa powder, baking powder, baking soda, and salt. In another bowl, whisk together the eggs, milk, vegetable oil, and 2 teaspoons of vanilla extract. Add the wet mixture to the dry ingredients and mix until combined. Stir in the hot water until the batter is smooth. Divide the batter between the prepared pans and bake for 28 to 32 minutes until a toothpick inserted in the center comes out clean. Cool the cakes in the pans for 10 minutes, then transfer them to racks to cool completely. Beat the remaining butter until creamy. Add the powdered sugar, remaining cocoa powder, remaining vanilla extract, and heavy cream and beat until smooth. Place one cake layer on a serving plate, spread with frosting, top with the second layer, and frost the top and sides.