Mile-High Lime Pie
["1 can (14 oz.) fat-free sweetened condensed milk", "1 c. (8 oz.) reduced-fat sour cream", "1/3 c. plus 2 Tbsp. lime juice", "5 drops green food coloring, optional", "1 carton (8 oz.) frozen reduced-fat whipped topping, thawed", "1 reduced-fat graham cracker crust (8 inches)"]
["In a bowl, combine the milk, sour cream, lime juice and food coloring, if desired. Fold in whipped topping. Pour into the crust. Refrigerate for at least 12 hours."]
["condensed milk", "sour cream", "lime juice", "coloring", "graham cracker crust"]