1/4 c. butter, soft
1/2 c. sugar
1 egg
1 c. flour
1 1/2 tsp. baking powder
1/2 tsp. salt
1/3 c. milk
2 c. blueberries, frozen or fresh

Cream first 3 ingredients. Add dry ingredients, alternately with milk to make smooth. Pour into 8 inch square pan. Spread blueberries over batter. Combine in small bowl; 1/2 cup sugar, 1/3 cup flour, 1/4 cup butter and 1/2 teaspoon cinnamon. Sprinkle over the top. Bake at 350 degrees for 30 minutes. Serve warm with Cool Whip or ice cream.

Double recipe for 9 x 13, but you can scant blueberries and still be plenty.