Delaware White Potato Pie - cooking recipe

Ingredients

1 1/2 cups mashed white potatoes (no salt added)
1 cup sugar
1/3 cup butter, softened
1 teaspoon vanilla
1/2 teaspoon salt
1 cup milk
4 egg yolks
1 teaspoon lemon
4 egg whites
1 uncooked 9 inch pie shell

Preparation

Mix all ingredients, except egg whites.
Beat egg whites until stiff. Gently fold into rest of ingredients.
Pour into a 9-inch pie shell.
Bake at 400 degrees until knife comes out clean. (About 35 minutes).