Preheat the oven to 350 degrees F.

For the crust, combine the graham cracker crumbs, sugar, and butter in a bowl. Press into a 9-inch pyrex pie pan, making sure the sides and the bottom are an even thickness. Bake for 10 minutes until firm and golden. Allow to cool completely.

For the filling, beat the egg yolks and sugar on high speed in the bowl of an electric mixer fitted with a paddle attachment for 5 minutes, until thick. With the mixer on medium speed, add the condensed milk, lime zest, and lime juice. Pour into the baked pie shell and freeze.

For the decoration, beat the heavy cream on high speed in the bowl of an electric mixer fitted with the whisk attachment until soft peaks form. Add the sugar and vanilla and beat until firm. Spoon or pipe decoratively onto the pie and decorate with lime. Freeze for several hours or overnight.

Note: If you have concerns about raw eggs, combine the yolks with 1/2 cup of the lime juice used in the recipe in a double boiler. Whisk constantly over medium heat until the mixture reaches 140 degrees. Use in place of the raw egg yolks, remembering to add the remaining 1/4 cup of lime juice to the filling mixture along with the condensed milk and zest.