1 1/2 c. cinnamon graham cracker crumbs
1/4 c. (1/2 stick) butter, melted

SWIRL:

Melt on very low heat/microwave: 1/2 c. sugar

FILLING:

3 (8 oz.) pkg. cream cheese, room temperature
1 1/4 c. sugar
1 c. (8 oz.) dairy sour cream
6 eggs
1 1/2 tsp. vanilla

Pat crust up sides and bottom of 9 inch springform pan. Melt chocolate chips and 1/2 cup sugar in microwave or very low heat.

Mix cream cheese (softened) adding 1 1/4 cups sugar slowly. Whip until well blended. Mix in sour cream and vanilla. Beat eggs in one at a time. Pour 2/3 of filling into prepared springform pan. Stir melted chocolate into remaining batter until well blended. Pour chocolate mixture over batter in swirl pattern. With a knife, swirl chocolate into plain to marbelize.

Bake at preheated 325 degree oven for 1 hour and 15 minutes. Place pan on sheet of foil to catch any drippings. Turn off oven heat and allow cake to remain in oven an additional hour to cool. Cool to room temperature on wire rack. Chill in refrigerator overnight before serving.