This is a good substitute for key lime pie.
1 (6-ounce) can frozen limeade concentrate, thawed
1 (14-ounce) can sweetened condensed milk
1 (8-ounce) container frozen whipped topping, such as Cool Whip, thawed
1 (9-inch) graham cracker piecrust
Mix limeade and sweetened condensed milk in a large bowl. Be sure it is completely combined. This will take longer than you think. Don’t be tempted to stir in whipped topping to early.
Fold in whipped topping.
Pour filling into graham cracker crust.
Chill 2-3 hours.