3/4 c. sugar
1/4 c. butter
2 eggs
1 tsp. vanilla
2 c. flour
2 tsp. baking powder
1/2 tsp. salt
1/4 tsp. cinnamon
1/2 c. buttermilk
2 1/2 c. frozen or fresh blueberries
Streusel Topping

Beat butter and sugar in large bowl with electric mixer at medium speed until well blended. Beat in eggs and vanilla.

Combine flour, baking powder, salt and cinnamon. Stir flour mixture and buttermilk alternately into sugar mixture until well blended. Stir in blueberries. Spoon batter into 9-inch square pan that is greased.

Prepare streusel topping. Sprinkle evenly over batter.

Bake at 375°F for 25 to 30 minutes or until toothpick comes out clean.

Streusel Topping:

1/4 c. flour
1/4 c. sugar
1/4 c. packed brown sugar
1/2 tsp. ground cinnamon
1/4 c. butter

Combine flour, sugar, brown sugar and cinnamon until well blended. Cut in butter with pastry blender or 2 knives until mixture resembles coarse crumbs.