Preheat oven to 350.
Combine flour, sugar, 1/4 C cocoa powder, baking powder and salt in 8 inch square baking pan. Stir with fork until well combined. Mix in milk and oil until batter is uniform.
Sprinkle brown sugar, 1/4 C cocoa powder and chocolate chips evenly over the batter. Add vanilla to the hot water and pour over everything. Do not stir.
Place pan in oven and bake for 30-35min. The surface of the cake will look dry but the "pudding" will be bubbling around the edges. Allow to cool just a few minutes before serving.