How to Make It
Preheat oven to 325°.
To prepare crust, combine first 3 ingredients; toss with a fork until moist. Press into the bottom of a 9-inch springform pan coated with cooking spray. Bake at 325° for 5 minutes.
To prepare filling, beat cheeses and sour cream in a large bowl with a mixer at high speed until smooth. Lightly spoon flour into a dry measuring cup, and level with a knife. Add the flour, sugar, and next 3 ingredients (sugar through vanilla extract), and beat well. Add the eggs and egg whites, 1 at a time, beating well after each addition.
Pour the cheese mixture into prepared pan; bake at 325° for 1 hour and 10 minutes or until almost set. Cheesecake is done when center barely moves when pan is touched. Remove the cheesecake from oven, and run a knife around the outside edge. Cool to room temperature. Remove sides.
To prepare the topping, combine marmalade and 1 tablespoon liqueur. Spread half of mixture over top of cheesecake. Cut the orange slices in half, and arrange over cheesecake. Spread with remaining marmalade mixture. Cover and chill at least 8 hours.