Optional garnish(es): candied pecans (recipe), candy corn or candy pumpkins, crystallized ginger, kumquats/candied kumquats (whole or halved), red/purple grapes (whole or sliced), shaved chocolate
1. PREHEAT oven to 500°F. Create a bain-marie: Place a pan of water on the bottom rack (or the bottom) of the oven. This creates a moist environment and will help prevent the top of the cheesecake from cracking. (You can wait and add the bain-marie when you insert the cheesecake pan into the oven.)
2. COMBINE gingersnaps, walnuts, sugar and butter in a medium bowl. Press into the bottom and 1-inch up the side of a 10-inch non-stick springform pan. Set aside.
3. BEAT cream cheese, sugar and flour with an electric mixer until smooth. Add 5 eggs, one at a time, then vanilla, beating on low speed. Transfer 2-1/2 cups to a separate bowl; set aside.
4. BEAT 1 egg, pumpkin pie spice and pumpkin into the remaining filling until smooth. Pour half of pumpkin filling into crust, then half of the plain; repeat. Swirl gently with a spoon.
5. BAKE for 10 minutes; reduce temperature to 200°F and bake 30 minutes. Tent with aluminum foil and continue baking for 1 hour or until center appears nearly set.
6. RUN a knife around top of the cheesecake to loosen it from the pan. Turn off oven and open door to allow cake to cool gradually for 20 to 30 minutes in the oven.
7. REMOVE from oven and finish cooling on a rack for 15 minutes, then chill in refrigerator for at least 6 hours. Garnish and serve.