Use this cake recipe as the base for Jason Schreiber's Gooey Caramel and Chocolate Cake with Salted Peanuts.
Preheat oven to 350 degrees. Butter one 8-inch round cake pan (2 inches deep); dust with cocoa. Sift cocoa, flour, sugar, baking soda, baking powder, and salt into the bowl of a mixer. Beat on low speed until just combined. Raise speed to medium, and add eggs, buttermilk, water, oil, and vanilla. Beat until smooth, about 3 minutes.
Pour batter into pan. Bake until set and a toothpick inserted into the centers comes out clean, about 35 minutes. Let cool for 15 minutes. Turn out from pan. Transfer, faceup, to wire rack. Let cool completely.
Chef's Note: Bake this recipe in one pan and split the cake into 2 layers after it's baked rather than baking it in two separate pans. You get more even layers this way!