Preheat your oven to 350°F (175°C). Set a rack in the center of the oven. Lightly grease a 9-inch glass or ceramic pie dish with butter or nonstick spray.

In a medium bowl, combine the graham cracker crumbs, granulated sugar, and 1/2 teaspoon fine sea salt. Stir with a fork until evenly mixed. Pour in the melted butter and stir until the crumbs are evenly coated and look like wet sand. If a handful crumbles apart when squeezed, add 1 more tablespoon melted butter.

Press the crumb mixture firmly into the bottom and up the sides of the pie dish. Use the bottom of a measuring cup or glass to compress the crust until compact and even. Bake for 8–10 minutes, until lightly golden and fragrant. Cool slightly on a wire rack while you prepare the filling; the crust can be warm but not piping hot when you add the filling.

Reduce the oven temperature to 325°F (165°C) to gently bake the filling.

In a large mixing bowl, whisk the egg yolks for 1–2 minutes, until they look slightly thicker and lighter in color. You can use a hand mixer on medium speed if you prefer.

Add the sweetened condensed milk to the yolks and whisk until smooth and well combined, scraping down the sides of the bowl as needed.

Slowly whisk in the lime juice, lime zest, vanilla extract, and a pinch of fine sea salt. The filling should be silky and slightly thick. Taste and, if desired, adjust tartness by adding a little more lime juice or sweetness with a spoonful of extra condensed milk or sugar.

Pour the lime filling into the partially baked graham cracker crust and smooth the top with a spatula.

Bake at 325°F (165°C) for 14–18 minutes, just until the edges look set and the center still has a slight jiggle when you gently nudge the pan. Do not overbake, or the filling can crack and become firm or eggy.

Remove the pie from the oven and let it cool at room temperature for about 1 hour. The filling will continue to set as it cools.

Once the pie is close to room temperature, cover it lightly with plastic wrap and refrigerate for at least 3–4 hours, or overnight, until thoroughly chilled and sliceable.

Just before serving, beat the cold heavy whipping cream, powdered sugar, and vanilla extract together with a hand or stand mixer until soft-to-medium peaks form.

Spread or pipe the whipped cream over the chilled pie, or add dollops around the edges. Garnish with extra lime zest or thin lime slices if desired. Slice with a sharp knife, wiping the blade between cuts for clean slices, and serve well chilled.