Preheat your oven to 350°F (175°C). In a medium bowl, combine graham cracker crumbs, sugar, and melted butter, stirring until the mixture resembles wet sand and holds together when pressed.

Press the crumb mixture firmly into the bottom and up the sides of a 9-inch tart pan with a removable bottom, using a flat-bottomed measuring cup to pack it tightly. Bake for 10 minutes until lightly golden and fragrant, then remove and let cool for 5 minutes. Leave the oven on.

While the crust cools, whisk together the egg yolks and sweetened condensed milk in a large bowl until smooth and slightly thickened, about 1 minute.

Add the lime juice, lime zest, and salt to the egg mixture, whisking until completely combined and the filling is pale yellow and pourable.

Pour the filling into the warm crust, spreading it evenly to the edges with a spatula. Tap the pan gently on the counter twice to release any air bubbles.

Bake for 15-17 minutes, just until the edges are set but the center still jiggles slightly when you gently shake the pan. The filling will look glossy and may have a few small bubbles.

Remove from the oven and let cool on a wire rack at room temperature for 30 minutes, then transfer to the refrigerator.

Chill uncovered for at least 3 hours or overnight until completely firm and cold. Remove the outer ring of the tart pan before slicing and serving.