For the crust:
1 1/2 cups ginger snaps
1/2 cup chopped pecans
1/4 cup firmly packed light brown sugar
1/4 cup granulated sugar
1/2 stick (1/4 cup) unsalted butter, melted.
For the Filling:
1 15-oz can pure pumpkin
3 large eggs
1 1/2 tsp. cinnamon
1/2 tsp. nutmeg
1/2 tsp. ginger
1/2 tsp. salt
1/2 cup firmly packed light brown sugar
3 (8 oz.) packages cream cheese, softened
1/2 cup granulated sugar
2 Tbsp. heavy cream
1 Tbsp. cornstarch
1 tsp. vanilla
1 Tbsp. bourbon liqueur or bourbon
Garnish: 16 pecan halves
Make the crust: In a bowl combine the cracker crumbs, the pecans and the sugars. Stir in the butter and press the mixture into the bottom and 1/2 inch up the side of a buttered 10-inch springform pan. Freeze the crust until filling is ready.
Make the filling: In a bowl, whisk together the pumpkin, egg, cinnamon, nutmeg, ginger, salt, and brown sugar. In a large bowl, with an electric mixer, cream together the cream cheese and the granulated sugar. Beat in the cream, cornstarch, vanilla, bourbon and the pumpkin mixture. Beat the filling until smooth. Pour the filling into the crust. Bake the cheesecake in the middle of a preheated 350º F oven for 50-55 minutes or until the center is just set. Let it cool in the pan on a rack for 5 minutes.
Make the topping: In a bowl, whisk together the sour cream (2 cups), sugar (1/2 cup), and the bourbon (1 Tbsp.).
Spread the sour cream mixture over the top of the cheesecake and bake the cheesecake for 5 minutes more. Let the cheesecake cool in the pan on a rack and chill it, covered, overnight. Remove the side of the pan and garnish.