Preheat the oven to 350°F (175°C). In a mixing bowl, combine graham cracker crumbs, sugar, and melted butter. Mix until well combined.

Press the mixture firmly into the bottom and up the sides of a mini pie pan. Bake for 8-10 minutes until golden. Remove from oven and let cool.

In a bowl, whisk together egg yolks, sweetened condensed milk, key lime juice, and lime zest until smooth.

Pour the filling into the cooled crusts and bake for an additional 10 minutes. Remove from oven and let cool.

In a mixing bowl, beat the chilled heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form.

Top each mini pie with a dollop of whipped cream before serving.