1/2 cup graham cracker crumbs
1 tablespoon granulated sugar
2 tablespoons butter or margarine, melted
1 square unsweetened chocolate, melted
3 packages (8 ounces each) cream cheese, softened
3/4 cup firmly packed brown sugar
1/4 cup granulated sugar
2 pints sour cream
1 tablespoon raged orange rind
6 squares semisweet chocolate, melted and cooled
1. Combine crumbs, the 1 tablespoon sugar, butter and unsweetened chocolate in small. Press into the bottom of a lightly buttered 8×3-inch springform pan. Refrigerate
2. Beat cream cheese in a large bowl until smooth. Gradually beat in sugars until well mixed. Beat in eggs, one at a time, until fluffy. Beat in sour cream and rind. Reserve 3 cups.
3. Beat cooled chocolate into the remaining cream cheese mixture until well mixed.
4. Spoon 1 cup of the reserved plain cheese mixture over crust in pan. Spoon half the chocolate-cheese mixture in 4 separate mounds over plain cheese layer. Cover with another cup of reserved plain cream cheese mixture. Repeat layers. Cut through batter with a zigzag motion to marble.
5. Bake in a preheated moderate oven (350-degrees) for 1 hour. Turn off oven; leave in oven for 1 hour. Cool on rack. Refrigerate overnight.
6. Remove from pan. Decorate with orange slices and chocolate leaves, if you wish.