Preheat oven to 350 degrees. Spray a 1.5 or 2 quart deep baking dish with a non-stick cooking spray. Set aside.
In a medium mixing bowl, combine flour, baking powder, salt, sugar and cocoa using a whisk or sift ingredients together. Stir in melted butter, milk, and vanilla. Spread mixture into prepared baking dish. Set aside.
In another medium bowl, combine the topping ingredients of both sugars, salt, and cocoa. Sprinkle dry mix on top of batter in baking dish. DO NOT STIR THE DRY MIX INTO THE BATTER. LEAVE AS IS.
Pour the boiling water over the dry mix in baking dish to cover. DO NOT STIR WATER INTO THE MIXES. LEAVE AS IS.
Bake for 30-35 minutes until the top of the cake is firm and almost set. (The cake will rise to the top and a pudding layer forms on the bottom. Allow to rest for a few minutes. Serve with ice cream of whipped topping.
