1/2 c. key lime juice, freshly squeezed
1 (14 oz.) can sweetened condensed milk
1 ready-crust graham cracker pie crust
1 (8 oz.) tub Cool Whip whipped topping

Mix the Cool Whip, condensed milk, and the key lime juice together, thoroughly using a blender, set on medium speed. You can also add a couple drops of green food coloring, if you desired. Pour the mixture into the pie crust and smooth over the top with a spatula. Chill in the refrigerator until firm.

NOTE: If you can't find key lime, use lime instead. This takes about 10 minutes at the most to make, from start to finish.