Preparation time: 10-15 minutes
Cooking time: 35 minutes
 

This cooking method not only offers a visual spectacle but also unrivalled cooking quality: these are the benefits of cooking à l'étouffée (the same principle as cooking en papillote, or in a parchment or foil package) but in a natural material, in this case Guerande coarse gray sea salt which is rich in trace elements. The salt crust seals and protects the foods like a shell, concentrating the flavors and cooking them in their own steam.

1. Gut but do not scale the fish.
2. Spread an even layer of coarse salt in a baking dish, place the fish on top and cover with an equal thickness of coarse gray Guerande sea salt.
3. Place in a 200° C (400° F) oven and cook for about 35 minutes.
4. Chop the shallots finely, place them in a heavy saucepan and add the vinegar and wine.
5. Bring to a boil, reduce gently until the liquid has evaporated and the shallots are cooked. Whisk in the butter one piece at a time.
6. To serve, break the salt crust, remove the fish and take off the skin. Spoon the beurre blanc over the fish fillets.