Crust

1. In a bowl combine cracker crumbs, pecans and the sugars.
2. Stir in the butter, and press the mixture into the bottom and 1/2 inch up the side of a buttered 9 inch springform pan.
3. Chill the crust for 1 hour.

Filling

1. Heat oven to 350 degrees F.
2. In a bowl whisk together pumpkin, egg, cinnamon, nutmeg, ginger, salt and brown sugar.
3. In a large bowl with an electric mixer cream together cream cheese and granulated sugar.
4. Beat in cream, cornstarch, vanilla extract, bourbon liqueur (if using) and pumpkin mixture until smooth.
5. Pour the filling into the crust.
6. Bake the cheesecake in the middle of the oven for 50 to 55 minutes, or until the center is just set.
7. Let the cheesecake cool in the pan on a rack for 5 minutes.

Bourbon Sour Cream Topping

1. In a bowl whisk together sour cream, sugar and bourbon liqueur.
2. Spread the sour cream mixture over the top of the cheesecake and bake the cheesecake for 5 minutes more.
3. Let the cheesecake cool in the pan on a rack and chill it, covered, overnight.
4. Remove the side of the pan, and garnish the top of the cheesecake with the pecans.