Lemon Custard Pie

1 cup sugar
1 tablespoon butter or margarine, softened
3 tablespoons all-purpose flour
1/8 teaspoon salt
2 eggs, separated
1 cup milk
1/4 cup fresh lemon juice
Peel of 1 medium lemon
1 unbaked pie pastry (9 inches)
Whipped cream, optional

Using a spoon, cream sugar and butter in a bowl until well mixed. Add flour, salt, egg yolks and milk; mix well. Add lemon juice and peel; mix well. Set aside. In a small bowl, beat egg whites until stiff peaks form; gently fold into lemon mixture.

Pour into pie shell. Bake at 325° for 1 hour or until lightly browned and a knife inserted in center comes out clean. Cool. Garnish with whipped cream if desired. Store in the refrigerator. Makes 6-8 servings.