- Combine flour, brown sugar, 3 tablespoons cocoa, baking powder and salt in a medium bowl.
- Add milk, oil and vanilla and mix well.
- Spoon batter into greased 8 or 9 inch square baking pan.
- Mix remaining cocoa and granulated sugar.
- Sprinkle over cake batter.
- Pour boiling water over batter.
- Bake at 350 degrees for about 30 minutes, until cake springs back when touched.
- Let cool on wire rack 5-10 minues.
- Serve warm.