Mix and cook in a glass microwavable bowl.
Sift together 2 cups flour, 3/4 cup sugar, and 2 tsp. baking powder. Add 1 cup blueberries. Stir in 1/2 cup melted margarine, 3/4 cup milk and 1 tsp. vanilla. Mix everything and put in microwave for 7 minutes.
Mix 1 cup brown sugar, 2 tbs. flour and 1/2 tsp. salt in saucepan. Add 1 cup boiling water and stir. Add 1/4 cup butter (margarine) and heat till melted and sauce becomes thick. Add 1/2 tsp. vanilla before serving.