Lightly spoon flour into a dry measuring cup; level with a knife.
Combine flour, 2/3 cup sugar, 1/4 cup cocoa, coffee granules, baking powder, and salt in a bowl.
Combine milk, oil, and vanilla in a bowl; add to flour mixture, and stir well. Spoon batter into an 8-inch square baking dish coated with cooking spray.
Combine 1/3 cup sugar and 2 tablespoons cocoa.
Sprinkle over batter.
Pour 1 cup boiling water over batter (do not stir).
Bake at 350 for 30 minutes or until the cake springs back when touched lightly in the center (cake will not test clean when a wooden pick is inserted in center).
Serve warm with ice cream.
Note: This recipe is easy to double. Spoon into a 13 x 9-inch baking dish; bake at the same temperature and time.