Position knife blade in food processor bowl; add 1 cup pistachio nuts. Process until chopped. Add wafer cookie crumbs, 3 tablespoons sugar, and melted butter. Pulse 4 or 5 times or until blended.
Press crumb mixture onto bottom and 1 1/2" up sides of a lightly greased 9" springform pan. Bake at 350° for 12 minutes or until lightly browned. Cool completely on a wire rack.
Bring whipping cream to a simmer in a heavy saucepan over medium heat. Remove from heat, and add chopped white chocolate. Let stand 2 to 3 minutes. Stir gently with a rubber spatula until smooth.
Beat cream cheese and softened butter at medium speed of an electric mixer until creamy. Add powdered sugar, and beat until light and fluffy. Add melted white chocolate mixture and vanilla; beat 3 minutes or until very smooth. Pour batter into prepared crust. Cover and freeze until firm or up to 1 week.
Let stand at room temperature about 30 minutes before serving. Remove sides of pan. Garnish cheesecake, if desired. Cut frozen cheesecake with a sharp knife, dipping knife in hot water and wiping it dry between each slice.