Blueberry Delight

1/4 cup butter, softened
1/2 cup sugar
2 eggs, beaten
1 cup flour
1 teaspoon baking powder
1/4 cup milk
1-1/2 cups fresh blueberries (frozen blueberries may be used)

SAUCE
1/4 cup butter, softened
1/2 cup sugar
1 egg yolk, well beaten
1/4 cup boiling water
Vanilla, to taste

Cream butter and sugar; stir in eggs. Sift flour and baking powder together. Add to creamed mixture alternately with milk, beating well. Coat blueberries with small amount of additional flour (to assure even distribution of berries in cake); fold into batter. Pour into lightly greased 8- or 9-inch square pan. Bake at 350 degrees for 30 minutes. Cut into squares. Top with sauce.

TO PREPARE SAUCE
Cream butter and sugar in top of double boiler. Blend in egg yolk and boiling water. Cook over hot water until mixture thickens, stirring frequently. Stir in vanilla. Spoon hot sauce over servings of Blueberry Delight.

SERVES: 6-8