To prevent the meringue from "weeping" you add cornstarch into the egg whites along with the sugar while you're making your meringue and be sure to add the meringue onto the top of the pie as soon as the filling is done so it's still super hot! It will cook the bottom of the meringue a little bit and that also helps prevent weeping.
Do not store this in the fridge before serving unless you absolutely have to.
1 cup white sugar
2 tbsp all purpose flour
3 tbsp cornstarch
1/4 tsp salt
1 1/2 cups milk
1/4 to 1/3 cup lemon juice + the zest (approx. 2 large lemon's zested and squeezed)
2 tbsp butter
4 egg yolks (beaten)
1 9" pie crust (either your fave homemade receipe or store bought)
5 egg whites
1/3 cup white sugar
1 tbsp corn starch
Make and bake your pie crust and let cool completely.
Preheat oven to 350 F.
Make your meringue first so it's ready to go lonto the pie as soon as the lemon filling is poured into the crust.
In a large bowl, whip your egg whites on high until foamy, add in the sugar and the cornstarch gradually and continue to whip until stiff peaks form. Set aside until the filling is ready.
Start by making your lemon filling. In a medium saucepan, whisk together the sugar, flour, cornstarch and salt. Stir in the water, lemon juice and lemon zest. Cook this over medium-high heat stirring frequently until it comes to a boil. Then stir in the butter. Place the egg yolks in a small bowl and beat, then slowly add in a 1/2 cup of the hot lemon mixture from the saucepan and mix well. Once that's done, whisk the egg yolk mixture into the saucepan as well. Continue to cook stirring constantly until thick. When it's done, immediately pour it into the cooled pie crust.
Top with the meringue immediately after your pour your pie filling. This will cook the bottom of the meringue a little bit and will help prevent weeping. Make sure you spread the meringue out completely and make a seal between the pie crust and meringue.
Bake in the oven for about 10 - 12 minutes until the tips of the meringue are golden brown and toasty.