1 1/2 c. flour
1/2 c. sugar
1 stick butter (1/2 c.), at room temperature, soft
1 1/2 tsp. baking powder
1 egg
1 tsp. vanilla
1 pt. blueberries
1 c. sour cream
1 egg yolk
1/2 c. sugar
1 tsp. vanilla

If using frozen blueberries, wipe away ice crystals with paper towel.

Preheat oven to 350 degrees. Generously grease 9-inch springform pan. Combine first 6 ingredients in large bowl and mix thoroughly. Turn into prepared pan and sprinkle blueberries evenly over top. Combine sour cream, yolk, sugar and vanilla. Blend well. Pour berries. Bake for 45 minutes or until edges of custard are lightly browned.