6 oz. chocolate chips
1 1/4 c. sugar
1 1/4 c. graham cracker crumbs
2 tbsp. sugar
1/4 c. melted butter
2 (8 oz.) pkgs. cream cheese
1/2 c. sour cream
1 tsp. vanilla
4 eggs

Combine chocolate chips and 1/2 cup sugar and heat over double boiler until smooth. Set aside. In a small bowl, combine graham cracker crumbs, 2 tablespoons sugar, and melted butter. Mix and pat into 9 inch pan. In large bowl, beat cream cheese until light and creamy. Gradually beat in 3/4 cup sugar. Mix in sour cream and vanilla. Add eggs, one at a time. Divide batter in half. Stir melted chocolate into half and pour into pan. Pour plain on top and swirl with a knife. Bake at 325 degrees for 50 minutes.