Festive Frozen Mint Pie

1 6-oz. Oreo pie crust

1 14-oz. can sweetened condensed milk

1 1/4 teaspoons peppermint extract

10 drops green food coloring -- optional

2 cups whipped topping -- thawed

Fresh mint leaves -- for garnish

In large mixer bowl, combine sweetened condensed milk, extract, and food coloring if desired. Fold in whipped topping. Turn into crust; cover. Freeze 6 hours or until firm. Garnish with mint leaves.