Foolproof Lemon Meringue Pie

This win - win lemon meringue pie is the perfect dessert recipe when you need a great pie. Making meringue has never been easier.
In a 2-to 3-quart skillet, combine 1 1/4 cups sugar with 6 tablespoons cornstarch and salt. Whisk with 1/2 cup cold water, lemon zest and lemon juice, and mix thoroughly. Whisk together the egg yolks. Add the butter and whisk with 1 1/2 cups of boiling water.Place the pan on a medium-high heat and stir with a flexible spatula until the mixture boils, about 7 minutes. Reduce the heat to medium and stir for another 1 minute.Pour the filling over the pie crust.In a small bowl, combine the remaining 1/2 cup sugar with the remaining 2 teaspoons cornstarch.In a deep bowl, beat the egg whites and tartar with a mixer on high speed (if using the whisk attachment) until a thick foam forms, leaving no liquid whites at the bottom of the bowl. Continue to beat on high speed and gradually add the sugar-starch mixture, 1 tablespoon at a time. Then beat until the whites are stiff, with shiny peaks.Spoon the meringue onto the hot pie filling. Using a spatula, beat the meringue until it completely covers the filling, touching the edge of the pie dish.Bake in the oven at 325 ° C until the meringue is lightly browned, about 25 minutes. Place the cake on a wire rack until it cools, about 3 hours. Serve or flip the cake in a large bowl (be careful not to touch the meringue) and refrigerate for up to 1 day.