this was sooo good. i used a devil's food cake-flavored cake mix and chocolate pudding mix instead of the vanilla.

cream cake dessert

Ingredients:
1 package (18-1/4 ounces) yellow cake mix
1 package (3.4 ounces) instant vanilla pudding mix
1/2 cup shortening
1 cup water
4 eggs

FILLING:
5 tablespoons all-purpose flour
1 cup milk
1/2 cup butter, softened
1/2 cup shortening
1 cup sugar
1 teaspoon vanilla extract
1/2 teaspoon salt

Directions:
In a large bowl, beat the cake mix, pudding mix and shortening on low speed until crumbly. Add the water and eggs; beat on medium for 2 minutes. Pour into a greased and floured 13-in. x 9-in. x 2-in. baking pan.
Bake at 350° for 30-35 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes; invert onto a wire rack to cool completely.
Meanwhile, in a small saucepan, combine flour and milk until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened. Cool completely.
In a large bowl, cream the butter, shortening, sugar, until light and fluffy. Beat in the milk mixture, vanilla and salt until smooth.
Split cake into two horizontal layers. Spread filling over the bottom layer; replace top layer.