In a microwave-safe 2-cup measure, stir together a heaping 1/3 cup granulated sugar, 1/2 cup King Arthur Unbleached All-Purpose Flour, 1 teaspoon baking powder, 1/4 teaspoon salt, and 2 tablespoons unsweetened cocoa powder. Add 6 tablespoons (3 ounces) milk, and a teaspoon of vanilla. Stir till smooth.
Mix 2 tablespoons brown sugar, 1 tablespoon granulated sugar, 1 tablespoon cocoa, and 3 tablespoons hot or cold coffee. Pour into the cup.
Gently swirl it in; don’t mix thoroughly.
Cook in the microwave for 2 1/2 to 3 minutes, depending how powerful your microwave is. When done, it’ll look set on top, and kind of mushy around the edges.
Turn the cake onto a plate. It’ll be layered with… well, let’s call it sauce. It’s actually semi-baked batter, but since there are no eggs in here, it’s fine.