To make pumpkin caramel cheesecake, combine cream cheese and sugar with pumpkin, whipping cream, cinnamon and allspice. Pour the filling into a crust made with ground cookies, pecans and sugar, then top with caramel sauce.
To make the crust for a pumpkin caramel cheesecake, grind 1 1/2 cups of gingersnap cookies with 1 1/2 cups of toasted pecans and 1/4 cup of firmly packed brown sugar. Add 1/4 cup of melted butter, blend until combined, and press the crust mixture into a 9-inch springform pan.
Using a mixer, beat 4 8-ounce packages of cream cheese at room temperature with 1 2/3 cups of sugar. Set 3/4 cup of this mixture aside to use for topping the cheesecake. Add 1 1/2 cups of canned pumpkin, 4 tablespoons of whipping cream, 1 teaspoon of ground cinnamon and 1 teaspoon of allspice to the remaining cream cheese mixture and beat well. Add 4 large eggs, one at a time, and beat just until combined. Pour the cheesecake filling into the crust and bake at 350 degrees Fahrenheit for 75 minutes, or until the cake is set in the center.
Cool the cheesecake for 10 minutes, run a small knife around the springform pan to loosen the sides, and refrigerate overnight. Add 5 tablespoons of whipping cream to the reserved 3/4 cup of cream cheese mixture and spread it evenly over the cheesecake. Spoon 1 tablespoon of prepared caramel sauce over the cheesecake and swirl it in with a knife. Release the cheesecake from the pan, and if desired, pipe sour cream onto the cheesecake prior to serving.