In a bowl, combine the flour, salt, baking powder sugar and 2 tablespoons cocoa. Stir in milk and oil. Pour into a 9-inch pie dish, baking dish or round skillet. Combine the brown sugar and remaining cocoa and sprinkle over batter. Pour hot water over top (do not stir). Bake for 40 to 45 minutes.
Let sit for about 20 minutes so it can set before topping with ice cream and serving.