Lime Mousse Cake

Crust
2 cups ground gingersnap cookies (about 38 cookies)
2 tablespoons sugar
5 tablespoons unsalted butter, melted

Filling
6 tablespoons Key lime juice or fresh lime juice
1 envelope unflavored gelatin
2 1/2 cups chilled whipping cream
9 ounces good-quality white chocolate (such as Lindt or Baker's), chopped
3 8-ounce packages cream cheese, room temperature
1 cup sugar
1 1/2 tablespoons grated lime peel

For crust: Combine ground cookies and sugar in processor. Add melted butter and process, using on/off turns, until moist clumps form. Press mixture onto bottom and 1 inch up sides of 10-inch-diameter springform pan. Bake at 350 degrees for 10 minutes. Cool.

For filling: Place lime juice in bowl. Sprinkle gelatin over to soften. Bring 1/2 cup cream to simmer in heavy medium saucepan. Remove from heat. Add white chocolate and stir until melted and smooth. Stir in gelatin mixture. Cool slightly. Using electric mixer, beat cream cheese, sugar and lime peel in large bowl to blend. Slowly beat white chocolate mixture into cream cheese mixture. Using clean dry beaters, beat remaining 2 cups whipping cream in another large bowl to peaks. Fold into white chocolate mixture. Pour filling into prepared crust. Cover and refrigerate overnight. (Can be prepared 2 days ahead. Keep refrigerated.) Release pan sides from cake. Transfer cake to platter and serve.