Filling

1 cup white sugar
2 tablespoons all-purpose flour
3 tablespoons cornstarch
1/4 teaspoon salt
1 1/2 cups water
2 lemons, juiced and zested
2 tablespoons butter
4 egg yolks, beaten
1 (9 inch) pie crust, baked

Meringue

4 egg whites
6 tablespoons white sugar

Preheat oven to 350 degrees F (175 degrees C).

Lemon Filling

In a saucepan, stir together sugar, flour, cornstarch, and salt.

Stir in water, lemon juice and lemon zest.

Cook over medium-high heat, stirring frequently, until mixture comes to a boil.

Stir in butter.

Place egg yolks in a small bowl and gradually stir in 1/2 cup of hot sugar mixture.

Stir egg yolk mixture back into remaining sugar mixture.

Boil and continue to cook, stirring constantly until mixture thickens.

Remove from heat and pour filling into baked pastry shell.

Meringue

In a large glass or metal bowl, whip egg whites until foamy.

Gradually add sugar and continue to whip until stiff peaks form.

Spread meringue over pie, sealing the edges at the crust.

Bake in the preheated oven for 10 minutes, or until the meringue is about golden brown.