To begin, preheat your oven to 350 degrees. Grease a 9×9 inch (or similar sized) baking pan. Set it aside for now.
In a mixing bowl, combine the flour, baking powder, sugar, salt, and baking cocoa. If you would like nuts in this dessert, add in the nuts. I leave them out if I am baking for friends with food allergies.
Stir those together, then add in the milk and melted butter. Mix until it forms a thick batter. Spread the batter in your baking pan.
In another bowl, combine 1/4 cup of baking cocoa and brown sugar. Sprinkle this dry mixture over the top of the batter in the pan.
Pour the hot water all over the top. Don’t stir anything. Simply place the pan in your oven and bake for 45 minutes.
When it is done baking, you will have a beautiful fudgy cake. And underneath the cake, you will discover a gorgeous chocolate sauce. Serve this warm with a scoop of vanilla ice cream.