First, make -- or buy! -- a graham cracker crust. Store-bought its totally fine here! If you want to go DIY, mix 1 1/2 cups of graham cracker crumbs, 1/3 cup of granulated sugar, 6 tablespoons of butter, and 1 tsp of cinnamon in a medium bowl. Stir to combine until it looks like wet sand, then pat into a 9" pie plate. Bake in an oven at 350F for 10-15 minutes, until it's firmer to the touch. Let it cool.
Next, mix 2 14-oz cans condensed milk, 1/2 cup of fresh lime juice, 1 tablespoon of lime zest, and 6 large egg yolks with a hand mixer or in the bowl of a KitchenAid for 3 minutes.
Pour the filling inside the pie crust and place Saran wrap on top -- put in the freezer and freeze for at least 3 hours.
Take the pie out about 5 minutes before you want to eat it, and top with whipped cream, additional lime zest, and slices of fresh lime if you want to make it pretty.