Preheat oven to 250 degrees F (125 degrees C).
In a mixing bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix well and press the mixture into the bottom of a 9-inch pie dish.
Bake the crust for 10-12 minutes, or until it starts to turn golden brown.
While the crust is baking, prepare the filling. In a large glass or metal bowl, beat egg whites until stiff peaks form. Set aside.
In a medium bowl, beat egg yolks, then stir in condense milk, lime rind and lime juice. Mix well, then fold mixture into beaten egg whites. Pour mixture into graham cracker crust.
Bake in preheated oven for 10 minutes, or until the center is set. Allow the pie to cool completely.
Chill before serving. Garnish with whipped topping if desired and lime zest for an extra touch of flavor.
