Directions
Preheat oven to 350 degrees
To make lemon filling: In a medium saucepan, whisk together 1 cup 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 whisk in 1/2 cup of hot sugar mixture. Whisk the yolk mixture into the remaining sugar mixture. Bring to a boil and continue to cook, stirring constantly, until thick. Remove from heat. Pour filling into baked pastry shell.
To make meringue: In a large glass or metal bowl, whisk egg whites until frothy. Add sugar gradually and continue to whisk until stiff peaks form. Spread the meringue over the pie, sealing the edges of the crust.
Bake in preheated oven for 10 minutes, or until meringue is golden brown.
