Lemon meringue pie is a basically a citrus curd pie save for the fact that the “curd” is made with a mixture of water and juice (instead of all juice), and it’s thickened with cornstarch. The water provides added volume (and frankly also keeps the flavor of the filling from becoming overwhelming) and the cornstarch provides thickening as well as insurance against curdling in the oven. This recipe — which steals tricks from both Rose Levy Beranbaum and Cook’s Illustrated — combines a deep pie with a break-resistant American-style meringue.
For the crust
For the Meringue
1 tablespoon cornstarch
2.5 ounces (scant 1/3 cup) water
1/4 teaspoon cream of tartar
3.5 ounces (1/2 cup) sugar
4 egg whites
For the Filling
3 ounces cornstarch (1/2 cup plus 1 tablespoon)
10.5 ounces (1 1/2 cups) sugar
1/4 teaspoon salt
8 egg yolks
16 ounces water (2 cups)
4 ounces (1/2 cup) lemon juice
1 1/2 tablespoons lemon zest
1 1/2 ounces (3 tablespoons) butter
Prepare the crumb crust mixture and press it into a 9″ pie pan. Alternately, prepare and pre-bake a conventional pie crust in a 9″ pie pan.
Preheat your oven to 350 degrees Fahrenheit.
Prep for the meringue step at this point. Combine the cornstarch and the water in a small saucepans bring it to a simmer, just at the point it starts to thicken. Remove the pan from the heat and set the mixture aside. Now’s also a good time to put your egg whites in a medium bowl (if you’re using a hand mixer) or in the bowl a mixer fitted with the whip. Also, whisk together the sugar and cream of tartar in a small bowl.
Now prepare the filling. Whisk the yolks together in a medium bowl. Whisk together the sugar, salt and cornstarch in a medium saucepan, then whisk in the water and lemon juice. Bring the mixture to a simmer over medium heat (it will start to thicken). Pour about half the hot mixture over the egg yolks and whisk vigorously to combine, then return everything to the saucepan. Whisk in the zest and the butter, and bring the mixture up to a simmer. Immediately remove it from the heat and set the pan aside, placing plastic wrap on the surface to prevent a skin from forming.
Promptly prepare the meringue. Whip the whites until they’re very frothy and have a little body to them, then whip in the sugar mixture. By then the whites will be at soft peaks. Add the cornstarch mixture and keep whipping to stiff peaks.
Lastly, assemble. Take the plastic off the filling and pour it into the prepared shell. Then immediately spread the meringue over the filling, making sure you get some over the crust edges (so it won’t pull away as it bakes). Bake it 20 minutes until the meringue is lightly browned. Cool it completely and serve the same day.