For the crust, combine the graham cracker crumbs, sugar, and butter in a bowl.
Press into a 9-inch pie pan, making sure the sides and the bottom are an even thickness.
Bake for 10 minutes. 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.
*RAW EGG WARNING.
Please use caution when consuming raw and lightly-cooked eggs due to the slight risk of Salmonella or other food-borne illness. To reduce this risk, it is recommended you use only fresh, properly-refrigerated, clean, grade A or AA eggs with intact shells, and avoid contact between the yolks or whites and the shell.