Base:

1 pkg. chocolate cake mix
3 eggs
1/3 c. oil
1 c. water

Filling:

1 tbsp. cornstarch
1 egg
2 tbsp. milk
1/2 tsp. vanilla

In small bowl, blend all filling ingredients. Beat at high speed until smooth and creamy. Set aside.

In large bowl, stir in all Base ingredients. Beat on high 2 minutes. Line cupcake pan with papers. Begin with Base mixture. Add a spoonful of filling and top with Base mixture.

Bake at 350°F until done. Frost if desired.