In a mixing bowl, combine margarine, milk, and the egg. Beat together.
Add the dry ingredients for the cake and stir into the milk mixture just until the dry ingredients are moistened.
Combine the topping ingredients.
Spread the cake batter in a heated Dutch oven, using ⅓ of the briquettes underneath and ⅔ on top. For a 12" Dutch oven, use a total of 32 (10 underneath, 22 on top). I added a couple more on the top to help with the browning of the top of the cake.
Sprinkle the topping over the batter.
Bake for 15 minutes.
Cut and serve!
