Steps
1. Preheat the oven to 350°F (175°C).
2. In a small bowl, mix graham cracker crumbs, sugar, and melted butter until combined.
3. Press the mixture into the bottom and sides of a small ramekin to form a crust.
4. Bake the crust for 8-10 minutes or until golden. Let it cool.
5. In another bowl, whisk together sweetened condensed milk, key lime juice, egg yolk, and lime zest until smooth.
6. Pour the filling into the cooled crust.
7. Bake for an additional 10-12 minutes. Let it cool to room temperature, then refrigerate for at least 2 hours.
8. Serve chilled, topped with whipped cream and a slice of lime.