Preheat oven to 325°F. Use 1–2 large pieces of aluminum foil to cover bottom and sides of 9-inch springform pan. (This technique will reduce leaks when using a water bath.) Add gingersnap cookies and walnuts to blender and run for 5 seconds.
Add butter, water, and cinnamon and run for 10 seconds. Press crust evenly into springform pan along bottom and up sides about 1 inch.
Clean blender, and add pumpkin, eggs, Neufchatel cheese, cream cheese, sugar, vanilla, salt, and pumpkin pie spice. Secure lid and blend. Pour filling over crust. Place springform pan inside of larger pan that is 2–3 inches deep.
Pour approximately 1 inch of boiling water into larger pan. Carefully place pan in oven, and bake for 90 minutes. (The center of cheesecake will jiggle but will complete cooking during the cooling process.)
Cool cheesecake completely, and then place in refrigerator until sufficiently chilled, about 10–12 hours. Serve with your favorite whipped cream or caramel topping.