GRAHAM CRACKER CRUST:

1 2/3 c. crushed graham crackers
1/4 c. sugar
1/4 c. + 2 tbsp. butter, melted

CHEESECAKE:

1 (12 oz.) pkg. semi sweet chocolate morsels
4 (8 oz.) pkgs. cream cheese, softened
2 c. sugar
1 tbsp. cocoa
1 (16 oz.) sour cream
4 eggs
2 tsp. vanilla

CRUST: Combine all ingredients mixing well. Press graham cracker crust mixture on bottom and 1/2" up the sides of a 10" springform pan.

FILLING: Melt chocolate morsels in double boiler or microwave. Beat cream cheese at high speed with electric mixer until light and fluffy. Gradually add sugar, mixing well. Add eggs, one at a time, beating well after each addition. Stir in melted chocolate, cocoa and vanilla, beat until blended. Stir in sour cream blending well. Pour into pan. Bake at 300 degrees for 1 hour and 40 minutes. Center may be soft, but will firm when chilled. Let cool to room temperature. Chill at least 8 hours.