1/2 c. butter, softened
1/2 c. sugar
1 egg
1 1/2 c. flour
1 1/2 tsp. baking powder
1 tsp. vanilla extract
4 c. fresh blueberries
2 (8 oz.) cartons sour cream
2 egg yolks
1/2 c. sugar
1 tsp. vanilla extract
1 1/2 c. whipping cream
1/4 c. powdered sugar
Blueberries for garnish

Cream butter; gradually add 1/2 cup sugar, beating well with electric miser. Add egg. Combine flour and baking powder. Add to creamed mixture until just blended. Stir in vanilla. Pour into greased 9-inch springform pan. Sprinkle with berries.

Combine sour cream and next 3 ingredients; pour over blueberries. bake at 350 degrees for 1 hour or until edges are lightly browned. Cool on rack, cover and chill.

To serve, remove from pan. Beat cream until foamy, gradually add sugar, beating until soft peaks form. Spread half of cream on top. Spoon remaining in decorating bag and pipe border around top. Garnish with blueberries.