whip the 3 egg whites until soft peaks and set aside.

beat egg yolks and 1 egg white, until thick.  add milk; beat again. add lime juice, beating until thick. Fold in 3 beaten egg whites; add a few drops of food coloring. Pour into pie shell; bake 15 minutes at 250 degrees until set.  Cool and Refrigerate.  Serve with topped with whipped cream.