There should be water in this recipe. We use the exact same recipe (on a bigger scale of course) to make our homemade chocolate cake (suprisingly enough it too is called a wacky cake), and it is the best cake EVER! Anyway, I think you'll want to add about a teaspoon of water to the recipe....maybe a touch more. :)
It was ok. The recipe calls for water yet no water in mentioned in the ingredients. I mixed in some milk and my daughter liked it ok.