For crust: In a medium mixing bowl stir together crushed graham crackers, walnuts and cinnamon. Stir in butter. If desired, reserve 1/4 cup for topping. Press remaining crumb mixture onto the bottom and about 2 inches up sides of an 8- or 9-inch springform pan. Set pan aside. For filling: In a large mixing bowl combine cream cheese, sugar, flour, vanilla and lemon peel (if using); beat with an electric mixer on medium speed till combined. Add eggs and egg yolk all at once, beating on low speed just till combined (do not overbeat). Stir in milk. Pour filling into crust-lined pan. If desired, top with reserved crumbs. Place on a shallow baking pan. Bake in a 375 oven for 45 to 50 minutes for 8 inch pan or 35 to 40 minutes for 9 inch pan, or till center appears nearly set when shaken gently. Cool in the pan on a wire rack for 15 minutes. Use a sharp, thin bladed knife to loosen the crust from the sides of the pan; cool for 30 minutes more. Remove the sides of the pan. Cool cheesecake completely. Cover and chill at least 4 hours before serving. Makes 12 t0 16 servings.

Low-Fat Berry Marble Cheesecake: Prepare crust as above, except reduce crushed graham crackers to 1/3 cup; omit walnuts and butter. Sprinkle onto bottom side of a well greased 8- or 9-inch springform pan. For filling, substitute three 8-ounce packages nonfat cream cheese for the regular cream cheese; add 1/2 cup refrigerated or frozen egg products (thawed) for the eggs and egg yolk. Prepare as directed. If desired, top with nonfat sour cream; spoon on seedless red raspberry preserves and swirl with a spoon.

Sour Cream Cheesecake: Prepare Cheesecake Supreme as directed, except reduce cream cheese to 2 packages and omit milk. Add three 8 ounce cartons dairy sour cream with eggs. Bake about 10 minutes longer than Cheesecake Supreme.

Chocolate Cheesecake: Prepare Cheesecake Supreme as directed, omiting lemon peel. Melt 4 ounces semisweet chocolate. Beat melted chocolate into filling mixture just before adding eggs.

Chocolate Swirl Cheesecake: Prepare Cheesecake Supreme as directed, omiting lemon peel. Melt 2 ounces semisweet chocolate. Stir melted chocolate into half the filling mixture. Pour chocolate mixture into crust; pour plain filling into crust. Gently swirl fillings with a spatula.