1-1/2 cups graham cracker crumbs 1/3 cup butter, melted 3 packages (8 ounces each) reduced-fat cream cheese, softened 1 cup plus 2 tablespoons sugar, divided 4 eggs 2 teaspoons vanilla extract, divided 1/4 cup unsweetened cocoa 1 container (16 ounces) reduced-fat sour cream Preheat the oven to 350 degrees F. In a medium bowl, combine the graham cracker crumbs and butter; mix well. Press into a 10-inch springform pan, covering the bottom and sides. Chill while preparing the filling.
In a large bowl, blend the cream cheese and 1 cup sugar with an electric beater. Add the eggs one at a time, beating well after each addition. Add 1 teaspoon vanilla and the cocoa; mix well, then pour into the chilled crust. Bake for 50 to 55 minutes, or until firm. Remove from the oven and let cool for 5 minutes. (Leave the oven on.)
In a medium bowl, with a spoon, mix the sour cream and the remaining 2 tablespoons sugar and 1 teaspoon vanilla until well combined. Spread over the top of the cheesecake and bake for 5 minutes. Let cool, then refrigerate overnight before serving.