Preheat your oven to 350 degrees F. This ensures that your crust comes out perfectly baked.
In a medium bowl, combine the melted butter and graham cracker crumbs. Mix it well until the crumbs are fully coated and crumbly.
Press this mixture into the bottom and up the sides of a 9-inch pie plate. Don’t worry about it being perfect; rustic is charming!
Bake the crust for 5 minutes, then remove it from the oven and let it cool while you prepare the filling.
In another medium bowl, use an electric mixer to beat the egg yolks until they’re pale and fluffy. This adds lightness to the filling!
Add the key lime zest, key lime juice, and sweetened condensed milk to the bowl. Blend well, scraping the sides and bottom to ensure everything is mixed smoothly.
Now, pour this luscious mixture into your cooled crust, spreading it evenly.
Bake the pie for about 15 minutes. You’re looking for a slight jiggle in the center; it will firm up as it cools.
Once done, let it cool at room temperature, then refrigerate for several hours or overnight. The longer it chills, the thicker it becomes!
When ready to serve, slice it up and garnish with whipped cream and key lime slices for that final touch.