1 can (14-oz) Sweetened Condensed Milk
1/3 cup lemon juice
2 tbsps flour
2 tsps grated lemon rind
Yellow food coloring, optional
Preheat oven to 375 degrees.
Bake pastry shell 10 minutes; remove from oven. Reduce oven temperature to 350 degrees.
In a large mixer bowl combine all the remaining ingredients except the egg whites; mix well.
In a small mixer bowl beat the egg whites until stiff but not dry; fold into the lemon mixture. Pour into the pastry shell.
Bake at 350 degrees 25 minutes until set. Cool.