To Make The Graham Cracker Crust:

1. Preheat oven to 350°F.
2. Stir together graham cracker crumbs, sugar, and butter in a bowl until evenly combined. Press mixture evenly onto bottom and up side of a 9-inch (4-cup) pie plate. Bake crust on the middle oven shelf for 10 minutes, then remove and let cool.

To Make The Filling:

1. While the crust is baking, make your filling. Combine mint leaves and lime juice in a shaker or glass. Use a muddler (or the end of a large wooden spoon) to muddle the mint into the lime juice. Then strain out the juice and discard the mint leaves.
2. In a separate mixing bowl, whisk together the condensed milk and egg yolks in a bowl until combined. Add the minty lime juice and rum (if using) and whisk by hand for 1 minute until combined and slightly thickened.
3. Pour filling into crust and bake on the middle oven shelf for 15 minutes. Transfer pie to a cooling rack, and let sit until it reaches room temperature. Then refrigerate for at least 3 hours, or until chilled and set.
4. Add optional toppings just before serving, if desired.