1/2 c. butter
1 c. sugar
3 eggs
1 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
1 c. white flour
1 c. whole wheat flour
1 c. sour cream
2 c. blueberries, frozen and thawed

TOPPING:

1 c. brown sugar
1/4 c. butter
1/4 c. white flour

Preheat oven to 350 degrees. Spray a 9 x 13 inch glass pan with cooking spray. Cream butter and sugar. Beat in eggs, soda, salt, and powder. Add flour and sour cream. Gently fold in blueberries. Pour batter into baking pan.

TOPPING: Cream together butter, brown sugar, and flour. Sprinkle topping over batter. Bake for 30 minutes or until an inserted toothpick comes out clean.