Combine first 5 ingredients in a heavy saucepan over medium heat, stirring often, 20 minutes or until temperature reaches 165°; remove from heat. Stir in lime rind; cool completely.
Beat whipping cream at high speed with an electric mixer until soft peaks form. Fold into egg mixture. Spoon into Gingersnap Crust.
Freeze 2 hours or until firm. Let stand 20 minutes before cutting. Garnish, if desired.
