Crust

4 tablespoon butter
3/4 cup graham cracker crumbs
1/2 cup crushed gingersnaps
1 tablespoon brown sugar (or your favorite substitute)
1 teaspoon cinnamon

Filling

1 cup heavy cream, chilled
24 oz cream cheese, softened
1 1/2 cups sugar
3 large eggs
1 1/2 cups mashed pumpkin
3/4 teaspoon ground cinnamon
3/4 teaspoon powdered ginger
3/8 teaspoon ground cloves
1/4 cup pecan halves

Place the butter in a small saucepan and melt over moderate heat.
Mix the graham cracker crumbs, gingersnaps, brown sugar and cinnamon in a medium bowl.
Add the melted butter and mix together with a fork.
Line bottom and side of 10" springform pan with parchment or wax paper.
Spray with nonstick pan spray.
Press the crumb mixture into the bottom.

Pour the heavy cream into a medium bowl and beat just until soft peaks form. Refrigerate.
Beat the cream cheese (in large bowl) with an electric mixer until fluffy. Gradually add the sugar, beating well.
Add the eggs one at a time, and beat the mixture until it is fluffy and pale. Stir in the pumpkin, cinnamon, ginger and cloves.
Remove the whipped cream from the refrigerator and whisk lightly to reblend. Using a spatula or flat spoon, fold the whipped cream into the cream cheese-pumpkin mixture.
Pour the mixture into the prepared crust.
Wrap one continuous sheet of aluminum foil around the springform pan and press firmly. Put wrapped pan in a baking pan and fill with hot water halfway up the spring from pan.
Bake for 60-70 minutes. Cool the cheesecake to room temperature, then refrigerate for at least 3 hours to chill thoroughly. Remove the sides of the springform pan. Just before serving, place the pecan halves on top of the cheesecake, in a ring around the edges, to garnish.