Preheat the oven to 400F.

In a large roasting pan or sheet pan (larger than the fish) line with parchment paper. Set aside.

In a large bowl, mix the salt, dried thyme and egg whites with your hands. It should be the consistency of a chunky paste. It won't be too wet and that is perfect. Set aside.

Remove the fish from the refrigerator and, if it hasn't been done at the market, scale the fish. Gut the fish (again, preferably done at the market) and remove the gills with kitchen shears. We recommend requesting this at the market before buying to make your life easier.

Cut the dorsal and pectoral fins and any other that is spiny or might stab you when you are ready to eat.

Stuff the fish cavity with the lemon slices, tarragon and rosemary. Place the fish on the parchment lined sheet pan.

Put the salt mixture on the fish and press it down forming a seal that is about ¼ inch thick around the entire fish. There should be no gaps or cracks and the fish should not be visible.

Put the fish in the preheated oven for 20 minutes. Some of the salt mixture may turn a light brown and the salt dome will be quite hard when finished.

While the fish roasts, prepare the sauce. Combine the wine, peppercorns and shallot in a small sauce pan over medium. Bring to a gentle boil and reduce the liquid by half.

Once the liquid has reduced by half, strain the solids through a sieve and return the strained sauce to the pan. Add the lemon juice and reduce to about 2 tablespoons of liquid. Once reduced, keep warm on low until your fish is ready.

Once your fish is ready and removed from the oven, set it aside while you finish the sauce.

To finish the sauce, remove the pan from the heat completely and let cool for a minute or two. You do not want the pan to be hot, but only warm so the sauce doesn't break. Whisk in the butter one piece at a time, emulsifying the mixture. If your butter isn't easily melting, you may need to return the pan to the burner (on low) briefly for about 30 seconds, but don't let your sauce get too hot during this process.

Once all the butter has been incorporated, you are ready to plate your dish.

To serve the fish, use a serving spoon to crack the salt dome and remove it from the fish. You want to have enough room to remove the fillets from the Branzino. With a sharp knife, slice the fish through skin at the end of the tail all the way to the bone. You can use your fingers, a knife, a spoon or a spatula to remove the skin from the tail toward the head. The skin should come off very easily without any effort.

Using the spoon, slide the spoon along the spine toward the head of the fish where the fillet stops. Remove to a clean plate. Gently flip the fish over and repeat to remove the opposite fillet. Serve with the lemon beurre blanc drizzled over the top with extra on the side as desired.