Mix the crust. In a medium mixing bowl, stir together the graham cracker crumbs, sugar, and butter until evenly combined. Press the mixture evenly into the bottom and up the sides of a 9-inch pie dish.
Bake. Bake for 10 minutes. Transfer pan to a wire rack until ready to add the filling.
To Make The Filling:
Whisk the filling. While the crust is baking, whisk together the condensed milk and egg yolks in a medium mixing bowl until combined. Add lime juice and zest and whisk by hand for 1 minute until combined and slightly thickened.
Bake. Pour the filling into pre-baked pie crust and bake the pie for 15 minutes. Transfer to a wire rack and let the pie cool until it reaches room temperature. Refrigerate for at least 3 hours, or until chilled and set.
Garnish. Top with whipped cream just before serving, if desired, sprinkled with a hint of lime zest and finished with a lime twist. Serve and enjoy!