In a mixer, add the egg whites and over the next 30 seconds start mixing from a low speed and gradually bringing it up to the highest speed setting.Bring a sauce pan to medium heat and stir together with a wooden spoon the sugar, water and lemon juice until it turns into a liquid.Pour the mix into the pie pans and bake for 10 minutes in the 350 degree oven.Once incorporated, mix in the lime zest with a spoon. In a blender add 2 cans of condensed milk, 6 eggs yolks, the key lime juice, and blend until well incorporated.Bake for 6 to 8 minutes or until the edges start to slightly brown.With your hand press the mix into a 6-inch springform pans covering all the bottom of the pan. The mixture should look like and have the consistency of slightly wet sand. Move the mixture to the bowl and incorporate the melted butter. Blend in the graham cracker crumbs to and incorporate together. Add the caramelized walnuts to a blender or food processor and process until they turn close to a powder.
