Preheat oven to 325°F. In bowl combine melted butter and graham cracker or gingersnap crumbs. Mix well to make crumbly mixture. Lightly grease 8-inch springform pan and press crumb mixture onto bottom, spreading it evenly.

Peel papaya and scoop out seeds. Separate a third of papaya and cut into thin slices. Set aside. Mash remaining papaya.

In electric mixer combine mashed papaya, cream cheese, sour cream, and sugar and beat until smooth. Add eggs and vanilla, and beat well. While beating, sprinkle in flour until well mixed. Pour mixture into prepared pan and bake 70 minutes or until center of cake is firm. Remove from oven and let cool 1 hour.

Decorate center of cake with papaya slices, making pinwheel design. Garnish cake edge with remaining slices and lightly dust with powdered sugar, if desired.