Heat oven to 400°F.
Combine 1/3 cup sugar and 1/2 cup butter in bowl. Beat at medium speed, scraping bowl often, until creamy. Add flour, 1 tablespoon lime zest, milk and vanilla. Beat at low speed until well mixed.
Press onto bottom and up sides of greased 10-inch tart or quiche pan. Bake 15-20 minutes or until light golden brown. Cool completely.
Combine 1 cup sugar, lime juice and 1 tablespoon lime zest in 2-quart saucepan. Cook over medium heat 1-2 minutes or until sugar is dissolved. Reduce heat to low.
Beat eggs and egg yolks in bowl with whisk. Stir small amount of hot sugar mixture into egg mixture using whisk. Gradually stir egg mixture into hot sugar mixture. Continue cooking, stirring constantly, 6-8 minutes or until mixture is thickened.
Remove from heat. Stir in 6 tablespoons butter, 1 tablespoon at a time, with whisk. Cool 15 minutes.
Pour cooled filling into crust; smooth top. Refrigerate at least 2 hours.
Just before serving, beat whipping cream in bowl at high speed, scraping bowl often, 2-3 minutes or until stiff peaks form. Place whipped cream in pastry bag fitted with large star tip. Pipe whipped cream onto tart; sprinkle with 2 teaspoons lime zest.
*Substitute regular lime zest and lime juice.