Step 1

Preheat the oven to 350 degrees F. Line a 12-cup muffin pan with 12 cupcake liners and set aside.

Step 2

In a mixing bowl, combine the graham cracker crumbs, brown sugar, and melted butter using a fork.

Step 3

Press about two tablespoons of the graham cracker mixture into the bottom of each cupcake liner, and bake for 5 minutes.

Step 4

While the crusts are baking, make the filling. Combine the 2 cans of condensed milk, key lime juice, and key lime zest in a large bowl. Whisk until the juice is thoroughly mixed. Add the egg yolks, and continue to whisk until the yolks are just combined. Do not over-mix the yolks.

Step 5

Pour the pie filling into each cupcake liner until almost full, about 3 Tablespoons each (I use a large cookie scoop for this).

Step 6

Bake the mini pies for 13-15 minutes or until the filling is completely set but not bubbling.

Step 7

Set the pies on a cooling rack for 1 hour, then cover (or place in an airtight container) and chill in the refrigerator for 3 hours, but overnight is best.

Step 8

Carefully remove the cupcake liners from the pies, top with whipped cream and lime zest, and serve chilled.