1 box Duncan Hines butter cake mix
1/3 c. sugar
4 eggs
1 c. buttermilk
3/4 c. oil
Frosting (below)
1 can blueberry pie mix

In mixer bowl, beat all ingredients together. Pour into 3 round cake pans and bake as directed on package. Frost each layer with frosting. Spread blueberry pie mix on each layer and over the top. Keep refrigerated.

FROSTING:

1 c. sugar
1 (8 oz.) pkg. cream cheese
1 stick butter
2 tsp. vanilla
1 lg. container Cool Whip

In mixing bowl, beat together sugar, cream cheese and butter. Add vanilla and Cool Whip.