6 EGGS: Separate the egg whites from the egg yolks into different bowls. Keep the yolks and set them aside. ( Make Hollandaise sauce with the yolks. Link Below)
Whip the egg whites into soft peaks using a whisk or hand mixer. Eggs closer to room temp will incorporate air quicker, which is the point of whipping the eggs.
Start adding the measured Kosher salt to the 6 whipped egg whites, plus the smoked salt,
Cooking The Fish
Preheat Oven To 450 degrees
Using an oven-safe baking dish. Add ⅓ of the salt/seasoning mix to the bottom of your bakeware dish. Spread out enough salt mix to cover the length of the fish.
Fill the fish cavity with sliced oranges or slices of Lemon, along with fresh parsley and fennel seeds. ( Crush the fennel seeds to add more flavor, there's an augment to not crush the fennel seeds as well. Depends on how much fennel flavor you want)
Place the fish, with head upward. Place on top of the ⅓ of salt/whipped-egg-whites
Add the remaining salt/egg-whites to the top part of the fish. Cover with as much as you like. Some people like keeping the head uncovered for preparation.
Using a spatula, you can add designs to the salt cast before cooking. Idea being adding scales like fish have for presentation.
Video
Keyword salt cast fish, Salt Crusted Branzino | MasterClass: Fish Technique Using SALT, salt crusted fish