3/4 cup all-purpose flour
3/4 cup granulated sugar
1 1/2 tsp baking powder
1/2 tsp baking soda
1/4 tsp salt
1/3 cup + 1/4 cup unsweetened cocoa powder
1/2 cup milk
3 tbsp butter, melted
1 tsp vanilla extract
1/2 cup firmly packed brown sugar
1 3/4 cups boiling water
Preheat oven to 350 degrees. Spray a 9-inch square baking pan or dish with nonstick cooking spray; set aside.
In a medium bowl, combine the flour, granulated sugar, baking powder, baking soda, salt, and the 1/3 cup cocoa. Combine the milk, butter, and vanilla in a measuring cup and stir the mixture into the dry ingredients just until blended. Spoon the batter evenly into the prepared pan.
Combine the brown sugar and 1/4 cup cocoa in a small bowl. Sprinkle the mixture over the batter in the pan. Pour boiling water over the entire mixture but do not stir! Bake at 350 degrees for 35 to 38 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before serving. Put onto a dessert plate or bowl and top with whipped cream or vanilla ice cream, if desired.