Grease two 10 x 3 inch round pans. Preheat the oven to 350F. Have all ingredients at room temperature.
In a bowl, combine and whisk until there are no lumps:
1 cups hot coffee
1 cup cocoa powder
Add and whisk until smooth:
1 cup cold water
On a piece of wax paper, sift together:
3 cups cake flour
2 teaspoons baking soda
½ teaspoon baking powder
¾ teaspoon salt
In the bowl of an electric mixer, beat at high speed until light and fluffy:
8 ounces (2 sticks) unsalted butter
2 ½ cups sugar
On medium speed, add slowly and cream well:
4 large eggs
1 ½ teaspoons pure vanilla extract
Add the dry ingredients alternately to the butter and egg mixture with the cocoa, mixing until smooth.
Pour 3 cups of the batter into one 10-inch pan and the remaining batter into the other 10-inch pan. Bake the less full pan for 20-25 minutes and the fuller pan for 30-35 minutes, or until a cake tester inserted into the center of the cake comes out clean. Cool the cakes on a wire rack for 15 to 20 minutes before turning them out of their pans.