Crust:
2 cups (200 grams) finely ground graham cracker crumbs2 tablespoons (24 grams) granulated sugar½ teaspoon (1.5 grams) kosher salt6 tablespoons (84 grams) unsalted butter, melted
Filling:
1½ cups (468 grams) sweetened condensed milk1½ tablespoons (4.5 grams) Key lime zest½ cup (120 grams) fresh Key lime juice4 large egg yolks (74 grams)½ teaspoon (2 grams) vanilla extract¼ teaspoon kosher salt
Topping:
1½ cups (360 grams) cold heavy whipping cream6 tablespoons (42 grams) confectioners’ sugar½ teaspoon (2 grams) vanilla extractGarnish: Key lime slices
Preheat oven to 350°F (180°C). Lightly spray a 9-inch ceramic pie plate with cooking spray.
For crust: In a medium bowl, whisk together graham cracker crumbs, granulated sugar, and salt. Stir in melted butter until well combined. (Crust should hold together when pressed). Using the bottom of a measuring cup, press mixture into bottom and up sides of prepared pan.
Bake until crust is fragrant and set, about 15 minutes. Let cool completely on a wire rack. Leave oven on.
For filling: In a large bowl, whisk together condensed milk, lime zest and juice, egg yolks, vanilla, and salt until well combined. Spread into prepared crust. Using a wooden pick, pop any bubbles on surface, if desired.
Bake until crust is golden brown, edges are set, and center jiggles slightly when plate is gently shaken, about 30 minutes. Let cool completely on a wire rack. Refrigerate until cold and set, at least 4 hours, or overnight. (Loosely cover pie once cold if refrigerating overnight.)
For topping: In the bowl of a stand mixer fitted with the whisk attachment, beat cold cream, confectioners’ sugar, and vanilla at medium speed until medium-stiff peaks form. Transfer mixture to a pastry bag fitted with desired piping tip; pipe whipped cream mixture onto cold pie as desired. Garnish with lime slices, if desired. Cover and refrigerate for up to 3 days.