1/2 c. butter, softened
1/2 c. sugar
1 egg
1 1/2 c. all-purpose flour
1 1/2 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. sifted powdered sugar
Blueberries for garnish

Cream butter; gradually add 1/2 cup sugar, beating well at medium speed of an electric mixer. Add egg, beat well. Combine flour and baking powder; add to creamed mixture and mix just until blended. Stir in 1 teaspoon vanilla. Pour into a greased 9 inch springform pan. Sprinkle with berries.

Combine sour cream and next 3 ingredients. Pour over blueberries. Bake at 250 degrees for 1 hour or until edges are lightly browned. Cool on a wire rack. Cover and chill.

To serve, remove cake from pan. Place on serving plate. Beat whipping cream until foaming, gradually add sugar, beating until soft peaks form. Spoon half of whipped cream over top of cake. Spoon remaining cream into a decorating bag and pipe a border around top. Garnish with fresh blueberries.