01 -
Stir graham cracker crumbs, sugar, melted butter, and salt in a medium bowl until the mixture looks like damp sand.
02 -
Divide the crust among mini tart pans or a muffin tin, pressing firmly onto the bottoms and up the sides. Chill for at least 30 minutes.
03 -
In a large bowl, whisk sweetened condensed milk, key lime juice, and lime zest until smooth and slightly thickened.
04 -
Spoon the filling into the chilled crusts and smooth the tops with a spatula.
05 -
Refrigerate the pies for at least 2 hours so the filling firms up.
06 -
Beat cold heavy cream with powdered sugar until stiff peaks form.
07 -
Pipe or dollop the whipped cream onto each pie and garnish with extra lime zest. Serve chilled.