1 c. graham cracker crumbs
3 tbsp. sugar
3 tbsp. butter, melted
3 (8 oz.) pkgs. Philadelphia cream cheese
3/4 c. sugar
3 tbsp. flour
1 tsp. vanilla
3 eggs
1 (1 oz.) square unsweetened chocolate, melted

Combine crumbs, sugar and butter; press onto bottom of 9" spring form pan. Bake at 350 degrees for 10 minutes.

Combine softened cream cheese, sugar, flour and vanilla, mixing at medium speed on electric mixer until well blended. Blend in eggs. Blend chocolate into 1 cup batter. Spoon plain and chocolate batters alternately over crust; cut through batter with knife several times for marble effect. Bake at 450 degrees for 10 minutes. Reduce oven temperature to 250 degrees; continue baking 30 minutes. Loosen cake from rim of pan; cool before removing rim of pan. Chill. Garnish with whipped cream, if desired.