1 9-inch pie shell, graham cracker, or baked and cooled pastry crust
1 14-ounce can sweetened condensed milk
1/2 cup key lime juice
1 8-ounce tub frozen whipped topping, thawed
2 to 3 teaspoons grated lime zest, optional
Instructions
In a mixing bowl with an electric mixer, beat sweetened condensed milk and key lime juice until smooth and thickened. Fold in the whipped topping and grated lime peel.
Spoon the mixture into the baked pie shell; cover and refrigerate for about 2 hours before serving, or until set, or freeze for 2 to 3 hours.