Sweet Potato Cheesecake

CRUST:
1 1/2 cups graham cracker crumbs
1/4 cup granulated sugar
1/3 cup butter or margarine -- melted
CHEESECAKE:
3 (8 ounces each) pkgs cream cheese -- softened
1 cup granulated sugar
1/4 cup light brown sugar
1 3/4 cups sweet potatoes, mashed
2 eggs
2/3 cup evaporated milk -- undiluted
2 tablespoons cornstarch
1/4 teaspoon ground cinnamon
1/8 teaspoon ground nutmeg
TOPPING:
2 cups sour cream -- room temperature
1/3 cup granulated sugar
1 teaspoon vanilla extract

Crust: Combine crumbs, sugar, and butter in bowl. Press onto bottom and 1 inch up on sides of 9 inch springform pan. Bake at 350° for 6 to 8 minutes. Do not allow to brown. Remove from oven and cool.

Cheesecake: Beat cream cheese, sugar and brown sugar in large bowl. Beat in sweet potatoes, eggs, and milk. Add cornstarch, cinnamon and nutmeg. Beat well. Pour into crust. Bake at 350 degrees for 55 to 60 minutes or until edge is set.

Topping: Combine sour cream, sugar and vanilla. Spread over warm cheesecake. Return to 350° oven and bake 5 minutes. Cool on wire rack. Remove side of pan and chill several hours or overnight.