Mix the ingredients and press them into a 9" pie plate. Bake in a preheated 350F oven for 10 - 12 minutes until lightly browned. Place on a rack to cool.
Use an electric mixer and beat the egg yolks until they are thick and turn to a light yellow, don't over mix. Turn the mixer off and add the sweetened condensed milk. Turn speed to low and mix in half of the lime juice. Once the juice is incorporated add the other half of the juice and the zest, continue to mix until blended (just a few seconds). Pour the mixture into the pie shell and bake at 350F for 12 minutes to set the yolks and kill any salmonella in the eggs.
If you are using the whipping cream garnish, prepare the cream. Serve with a dollop of whipped cream.