Preheat oven to 350F.
To make the Graham Cracker crust, combine the white granulated sugar and the Graham Crackers in a food processor with the Kosher salt.
Process until the Graham Crackers are all broken up and crumbled into a fine crumb.
Once that's done, pour in the melted butter, and pulse the food processor a few more times until the mixture forms a uniform crumbly texture.
Take the mixture and firmly press it into the bottom and up the sides of a 9” pie pan.
Pre-bake the crust, without the filling, for about 6-7 minutes at 350F.
Remove the pie pan with the crust from the oven after 6-7 minutes, and allow it to cool while we prepare the filling.
For the key lime filling, whisk together the egg yolks with the sweetened condensed milk until they're well combined.
Add in the lime zest and the lime juice, and whisk until combined.
Pour the filling into the pie pan with the pre-baked crust, and put the pie back in the oven to bake for roughly 16-18 minutes.
After about 16-18 minutes, remove the pie from the oven, and let it cool down to room temperature on a cooling rack.
Place the pie in the fridge, and allow it to chill for several hours or overnight in order for it to set properly.
When your pie has fully cooled and set in the fridge, it is time to make the whipped cream topping.
Grab some cold heavy whipping cream and whisk it in a cold bowl until you see soft peaks forming.
Then, whisk in the vanilla extract and powdered sugar until the mixture becomes integrated.
Continue to whisk until your whipped cream has reached the desired stiffness.
Now, get a pastry bag with a large star tip, and add the whipped cream mixture to the bag.
*If you don’t have a star tip with a pastry bag, don’t worry! You can use a ziplock bag, and cut a little hole in the bottom corner.
Use a piping bag or rubber spatula to gently and evenly distribute the whipped cream mixture evenly over the top of the key lime and condensed milk layer.
Sprinkle some more key lime zest on top, and garnish with some sliced key limes.
Serve cold, and store in the fridge when not serving.