Chocolate Swirl Muffin Cake

** Recipe from Betty Crocker **

Filling
* 1 c. semisweet chocolate chips
* 3/4 c. whipping cream
* 1 tsp. vanilla

Cake
* 2 boxes (16.4 oz each) Betty Crocker® chocolate chip premium muffin mix
* 1 1/3 c. water
* 1/2 c. vegetable oil
* 4 eggs

Heat oven to 375°F. Generously grease 12-cup fluted tube cake pan. In 2-quart saucepan, cook all filling ingredients over medium-low heat 2 to 3 minutes, stirring constantly, until smooth. Remove 1/3 cup filling for glaze; set aside. Freeze remaining filling 15 minutes until thick like pudding. Meanwhile, in large bowl, stir together all cake ingredients. Spoon half the batter into pan. Remove filling from freezer. Carefully spoon filling in center of batter to within 1/2 inch of pan edges. Spoon remaining batter over filling. Bake 50 to 65 minutes or until top springs back when touched. Cool 15 minutes. Remove from pan to wire rack. Spoon reserved 1/3 cup filling on cake to glaze. (If too thick, microwave filling on High 10 to 15 seconds using microwavable small bowl.) Cool completely, about 1 hour. High Altitude (3500-6500 ft): In step 2, cook filling ingredients over medium heat 2 to 3 minutes. Freeze remaining filling 20 minutes.