Grate the rind and juice 2 lemons. Use additional lemons if needed to get ⅓ cup lemon juice.
Mix together sugar, flour, cornstarch, and salt. Set aside.
Separate 4 eggs. Beat yolks and set aside. Put egg whites into a mixing bowl to make meringue.
Boil 2 cups of water. Add sugar mixture. Cook and stir until thickened and no longer milky looking. Add a small amount of mixture to egg yolks and stir well. Add yolk mixture back to pan and stir. Add lemon juice and rind, stir, and set aside to cool.
To make meringue, whip 4 egg whites at medium high speed. When soft peaks start to form, add salt and slowly sprinkle in sugar. Continue to whip until stiff peaks form.
Add cooled lemon filling to your pre-baked pie crust. Top with meringue. Use back of spoon to make peaks.
Bake in a 350 degree oven for 10 -15 minutes until meringue is golden brown.