Preheat the oven to 350F. Line two baking sheets with parchment paper. In a large bowl, sift the flour, sugar, baking soda, baking powder, and cocoa powder. Add the eggs, coffee, buttermilk, oil, and vanilla and beat at medium speed until combined the batter will be thin. Divide the batter evenly onto the baking sheets. Bake for 12 to 15 minutes, or until a cake tester comes out clean. And more. Download the full recipe now.