BASE:

1 pkg. Pillsbury Plus Devils Food cake mix
3 eggs
1/3 c. oil
1 c. water

FILLING:

8 oz. pkg. cream cheese
2 tbsp. butter
1/4 c. sugar
1 tbsp. cornstarch
1 egg
2 tbsp. milk
1/2 tsp. vanilla

Blend all filling ingredients until smooth. Blend remaining ingredients until moistened. Beat 2 minutes at highest speed. Pour half of batter into a greased and floured pan. Pour filling over, then remaining batter. Cool and frost with frosting of your choice. Store in refrigerator.