Preheat your oven to 350°F (175°C).
In a medium bowl, combine the graham cracker crumbs, granulated sugar, and melted butter. Mix until the crumbs are evenly coated.
Press the crumb mixture firmly into the bottom of a mini muffin tin to form a crust. Bake for 8-10 minutes until lightly golden. Remove from the oven and let cool.
In a separate bowl, whisk together the sweetened condensed milk, key lime juice, egg yolks, and lime zest until smooth.
Pour the key lime filling into the cooled crusts, filling each mini pie about 3/4 full.
Bake for an additional 10-12 minutes until the filling is set but still slightly jiggly in the center.
Remove from the oven and let cool to room temperature, then refrigerate for at least 2 hours to chill.
Before serving, top each mini dessert with a dollop of whipped cream and a slice of lime for garnish.