Beat egg yolks at medium speed of an electric mixer until thick and lemon colored. Heat Key lime juice over medium heat until hot. Gradually stir about one-fourth of hot lime juice into egg yolks, and add to remaining hot lime juice, stirring constantly. Cook, stirring constantly over medium heat for 2 minutes, or until mixture is thickened. Remove from heat and cool. Add sweetened condensed milk and lime rind, stirring well.
Spoon filing evenly into baked pastry shells. Chill until ready to serve. Remove tartlets from pans, and top each with whipped topping and lime wedges. Yield: 24 tartlets.
Cream Cheese Pastry
Preheat oven to 400º F.
Beat butter and cream cheese until smooth and fluffy. Add flour, beating well. Shape Cream Cheese Pastry dough into 24 balls. Place in non-stick, ungreased miniature (1¾ - inch) muffin pans, shaping each into a shell. Chill 15 minutes. Prick each shell, and bake at 400° F for 10 to 12 minutes or until golden brown. Loosen edges of tart shells from pans, using a sharp knife; do not remove from pans. Let cool completely on wire racks. May be prepared in advance and stored in a zip lock bag. Note: Can use prepared pie dough cut with 2¾-inch cutter in place of the cream cheese pastry.