1/2 c. butter, softened
1/2 c. sugar
1 egg
1 1/2 c. all-purpose flour
1 1/2 tsp. baking powder
1 tsp. vanilla
4 c. fresh blueberries
2 (8 oz.) cartons sour cream
2 egg yolks
1/2 c. more sugar
1 tsp. more vanilla
1 1/2 c. whipping cream
1/4 c. sifted powdered sugar
Garnish: blueberries

Cream butter; gradually add 1/2 cup sugar, beating well at medium speed of an electric mixer. Add egg, beating well. Combine flour and baking powder; add to creamed mixture and mix until blended. Stir in 1 tsp. vanilla. Pour into a 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 a wire rack; cover and chill.