Directions

1. Preheat an oven to 325 degrees F (165 degrees C). Grease a 9x13-inch baking dish.
2. Sift the flour and baking powder together in a small bowl. Beat the egg, sugar, and 1/4 cup margarine together in a large bowl. Add the flour mixture alternately with the milk to the egg mixture, stirring just to combine. Pour the batter into the prepared dish.
3. Bring the water to a boil in a saucepan; stir the brown sugar, 1/4 cup margarine, and vanilla extract into the water and return to a boil for 2 minutes. Pour the sauce over the batter.
4. Bake in the preheated oven until the center is set, about 45 minutes.