Graham cracker crust
3 (8 oz.) pkgs. cream cheese, softened
3/4 c. sugar
1/2 c. sour cream
2 tsp. vanilla
3 tbsp. flour
3 eggs
1/4 c. cocoa
1/4 c. sugar
1 tbsp. vegetable oil
1/2 tsp. vanilla

Prepare graham crust; set aside. Combine cream cheese, 3/4 cup sugar, sour cream and 2 tablespoons vanilla in large mixing bowl; beat on medium speed until smooth. Add flour, 1 tablespoon at a time, blending well. Add eggs; beat well. Combine cocoa and 1/4 cup sugar in small bowl. Add oil, 1/2 teaspoon vanilla and 1 1/2 cups of the cream cheese mixture; mix until well blended.

Spoon plain and chocolate mixtures alternately into prepared crust, ending with dollops of chocolate on top; gently swirl with knife or spatula for marbled effect. Bake at 4350 degrees for 10 minutes; without opening oven door, decrease temperature to 250 degrees and continue to bake for 30 minutes. Turn off oven; let cheesecake remain in oven 30 minutes without opening door. Remove from oven; loosen cake from side of pan. Cool completely; chill thoroughly.