1 (14 oz.) can sweetened condensed milk
3 egg yolks
1 1/2 tsp. lime rind, grated
1/3 c. fresh lime juice
3-4 drops green food color
1 (4 1/2 oz.) carton Cool Whip
1-2 tsp. white rum (optional)
1 baked pie shell

Heat oven to 250 degrees. Mix milk and egg yolks thoroughly. Add lime juice, lime and food color; mix. Pour into shell and bake for 10 minutes or until firm. Cool at room temperature. Chill thoroughly in refrigerator. Mix Cool Whip with white rum - top with Cool whip.