CRUST:

Marble cake mix
2 tbsp. oil
1 egg

FILLING:

1/2 c. sugar
1/2 c. sour cream
1/2 c. milk
2 (8 oz.) cream cheese, softened
2 eggs
1 tsp. vanilla

Heat oven to 350 degrees. Grease 9x13 inch pan. Reserve 1 cup dry cake mix and marble pouch; set aside.

In large bowl, combine remaining cake mix, oil and 1 egg at low speed until soft dough forms. Press in bottom and 1 1/2 inches up sides of greased pan. Bake at 350 degrees for 10 minutes; crust will not be browned.

In large bowl, combine reserved 1 cup cake mix, sugar, sour cream, milk, cream cheese, eggs and vanilla; mix at low speed until blended. Beat 3 minutes at medium speed or until creamy and smooth. Pour 2/3 of filling over warm crust. To remaining filling, add chocolate pouch; mix at low speed until well blended.

Spoon chocolate mixture randomly over cheese mixture. Pull knife through batter in wide curves; turn pan and repeat for marble effect. Bake at 350 degrees for 35 to 45 minutes or until center is set. Cool completely. Store in refrigerator. 15 to 20 servings.