Preheat the oven to 350°F (177°C). Line a standard muffin pan with 16 liners.

Combine graham cracker crumbs, melted butter, and granulated sugar in a medium bowl until the mixture is coarse and resembles wet sand. Add more butter if needed to reach consistency.

Press about 1 tablespoon of the mixture into each liner, making sure it is compact. Pre-bake the crusts for 6 minutes.

Using an electric mixer with a paddle attachment, beat the cream cheese until smooth. Add egg yolks, then gradually mix in sweetened condensed milk, lime zest, salt, and key lime juice until combined.

Pour the filling evenly into each crust. Bake for 15 minutes or until the pies are mostly set but the centers slightly jiggle.

After removing from the oven, cool at room temperature, then refrigerate for at least 2 hours. Decorate with whipped cream and additional lime zest for garnish.