Instructions

• Use the prepared 19-inch prebaked pie crust (213 g). If your crust is not already prebaked, prebake per your crust recipe or package directions and cool completely before filling.
• Make the lemon filling: in a large saucepan over medium heat whisk together 1¼ cups (250 g) granulated sugar, 1 cup (227 g) fresh lemon juice, ½ cup (114 g) water, ¼ cup (28 g) cornstarch, and ½ teaspoon kosher salt until the cornstarch is fully dissolved.
• Cook the mixture, stirring occasionally, until it comes to a simmer and begins to thicken and become translucent, about 5 minutes.
• Meanwhile, whisk the 4 egg yolks (56 g) in a separate bowl until smooth.
• Temper the yolks: slowly whisk about ½ cup of the hot lemon mixture into the yolks to raise their temperature (pour in a thin stream while whisking). Then whisk the tempered yolk mixture back into the saucepan.
• Return the pan to medium heat and, stirring constantly, bring the mixture to a simmer. Cook for an additional 2 minutes, or until the filling is thick enough to coat the back of a spoon without sliding off.
• Remove the pan from the heat and stir in 2 tablespoons (12 g) grated lemon zest and 3 tablespoons (42 g) unsalted butter, stirring until the butter is fully incorporated.
• Strain the hot filling through a fine-mesh strainer into the prepared (prebaked and cooled) pie shell, scraping the underside of the strainer so all filling passes through. Press a piece of plastic wrap directly onto the surface of the filling to prevent a skin from forming. Chill in the refrigerator until set, at least 2 hours and up to 24 hours.
• When the filling is chilled and set, preheat the oven to 400°F and move the oven rack to the middle position.
• Make the hot sugar syrup for the meringue: in a small saucepan over medium-high heat combine ½ cup (114 g) water and 1 cup (200 g) granulated sugar. Bring to a vigorous boil and once boiling cook exactly 4 minutes. Remove from the heat and transfer the syrup to a heatproof container.
• In the bowl of a stand mixer fitted with the whisk attachment, beat the reserved 4 egg whites (from the separated eggs) with ¼ teaspoon kosher salt and ½ teaspoon cream of tartar at medium speed until frothy, about 1 minute. Increase speed to medium-high and beat until the whites hold soft peaks, about 2 minutes.
• With the mixer running on medium-low to medium, very slowly pour the hot sugar syrup in a thin, steady stream down the inside of the bowl into the egg whites (avoid pouring directly onto the whisk to prevent splatter). Once all the syrup is added, increase speed and beat until the meringue is thick, glossy, and cooled to room temperature, about 7–10 minutes. Add ½ teaspoon (2 g) pure vanilla extract in the last minute of beating and mix to combine.
• Assemble the pie: remove the plastic wrap from the chilled lemon filling. Mound the meringue over the filling and press it against the crust all the way around to seal the meringue to the crust (this helps prevent weeping). Build up more meringue toward the center and use a spoon or spatula to create peaks as desired.
• Place the pie on a baking sheet and bake in the preheated 400°F oven until the meringue peaks are lightly golden brown, about 5–8 minutes—watch closely to avoid over-browning.
• Remove the pie from the oven and transfer to a cooling rack. Let cool before serving. If you prefer a more dramatic, even browning, you may lightly toast the meringue with a kitchen torch (exercise caution and keep a close eye for any flare-ups).