Lemon Meringue Pie

Ingredients

1 (9-inch) frozen pie crust (see pie crust recipe for instructions to make your own, use a deep-dish pie crust if store-bought)
For the lemon filling:
5 large egg yolks
6 tablespoons cornstarch
1 1/3 cup (266g) sugar
1/4 teaspoon kosher salt
1 1/2 cups water
1/2 cup lemon juice
2 teaspoons lemon zest
2 tablespoons unsalted butter
For the meringue:
1 tablespoon cornstarch
1/3 cup water
1/4 teaspoon cream of tartar or 1 teaspoon white vinegar