Preheat oven to 350º F. Position the rack in the center of the oven.

For the Crust:
Wrap double layer of heavy-duty foil around outside of 10-inch springform pan, all the way to the top. Combine cookies, pecans and brown sugar in a food processor. Blend until mixture is fine and uniform. Drizzle butter over mixture. Using the pulse setting, blend until crumbs begin to stick together. Press crumbs onto the bottom, only, of prepared pan. Bake 10 minutes, until crust is slightly golden. Transfer to wire rack and cool while preparing filling. Maintain 350°F oven temperature.

For the Filling:
Using an electric mixer, beat 2 pounds cream cheese until smooth. Add sugar; beat until smooth and fluffy. Beat in eggs one at a time, just until blended; do not over beat. Add pumpkin, whipping cream and vanilla; beat just until blended. Combine remaining six filling ingredients in a small bowl; beat into mixture just until blended. Pour into prepared crust. Place into a large roasting pan and add enough water to come halfway up sides of springform pan (a water bath).

Bake cheesecake until slightly puffed, softly set and the top is golden; about 1½ hours. Turn oven off. Do not open door; leave cheesecake in oven for additional ½ hour. Transfer springform pan to wire rack and cool to room temperature; remove foil. Cover and refrigerate cheesecake overnight. Leave in pan until ready to add topping and serve.

For the Topping:
In a medium bowl, combine butter, cream cheese,confectioners' sugar and vanilla. Beat until the mixture is smooth and creamy.

To Serve:
Run a hot knife around the inside of the springform pan; remove the side. Spread topping on cheesecake. Yield: 16 servings.