Preheat oven to 350. In a 9x13 glass baking dish, melt the two sticks of butter in the oven.
Meanwhile in a bowl, mix together the 1 1/4cups of sugar, flour, vanilla and milk. Once the butter is melted pour the batter over the butter, but do not stir.
In a separate bowl mix together the cocoa and remaining sugar.
Sprinkle cocoa/sugar mixture on top of batter. Do not stir.
Pour the 2 cups of boiling water on top of that (don't stir) and bake for 30-45 minutes. I bake mine until I have a nice golden brown crust. In my oven this usually take about 35 minutes. Serve warm. Great with ice cream