Center the oven rack; preheat oven to 375°F.
Tip all ingredients into a large bowl, finishing with the boiling water (or coffee). Beat, with electric beaters, until smooth -- about 2 minutes.
Divide the the batter between 2 greased 8-inch round cake pans. Alternatively, the batter can be poured into 1 greased 9x13- or 8x12-inch baking dish.
Bake until the batter browns and puffs slightly, and a skewer inserted into the cake comes out clean -- 20-25 minutes for 2 8-inch cake pans or 1 9x13 baking dish; 25-30 minutes for 1 8x12-inch baking dish.
Cool on a wire rack. When completely cool, the cake can be glazed or frosted. I simply dusted mine with confectioners' sugar. 'Twas delicious with coffee for breakfast.