Lemon Meringue Pie

1 C white sugar
2 Tbs flour
3 Tbs corn starch
¼ tsp salt
1 ½ C water
6 Tbs lemon juice
2 Tbs butter
4 egg yolks, beaten
1 9 inch pie crust, baked (for 8 min at 350)
4 egg whites
6 Tbs sugar

Preheat oven to 350 degrees.
Filling:
In double boiler, whisk together sugar, flour, cornstarch, and salt. Stir in water, lemon juice and 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 ½ cup of the hot sugar mixture. Whisk egg yolk mixture back into remaining sugar mixture. Bring to a boil and continue to cook while stirring constantly until thick. Remove from heat. Pour filling into baked pie crust.
Meringue:
In large bowl, whip egg whites until foamy. Add sugar gradually, and continue to whip until stiff peaks form. Spread meringue over pie, sealing edges at the crust. Form peaks all over top with knife touching and lifting up. Bake for 10 minutes or until meringue is golden brown.