Preheat the oven to 350°F.

In a small bowl, combine the lime juice, egg yolks, sweetened condensed milk, and vanilla extract. Whisk until incorporated. Pour into a small baking dish and bake for 18 minutes. Remove from oven and let cool. Once cooled, refrigerate for 4-6 hours. Then scoop it into a piping bag with no tip and put it back in the refrigerator.

In a food processor, pulse the graham crackers to fine crumbs. Add the butter and ¼ cup sugar and pulse until well combined.

Pour the cold heavy cream into a stand mixer bowl, fitted with a whisk attachment. Beat on medium until peaks begin to form. Add 2 tablespoons of sugar and continue beating until medium peaks form.

To assemble, spoon a layer of graham cracker crust into the bottom of a mini parfait glass. Pipe on a layer of key lime filling, then a spoon of whipped cream. Repeat those layers.