Gather the ingredients. Position a rack in the center of the oven and heat to 350 F.
In a medium bowl, combine the egg yolks and sweetened condensed milk.
Beat with a mixer at high speed until light and fluffy, about 5 minutes.
Gradually beat in lime juice and lime zest .
Pour mixture into the baked or store-bought graham cracker crust.
Bake until the filling sets up, but has a slight jiggle in the center, about 10 to 15 minutes.
Let cool to room temperature and then refrigerate for at least 2 hours.
If desired, decorate with whipped cream or slice and serve with a dollop on each serving.
