Instructions:
1. Combine 2 kg of salt and the egg white and mix until you have a sort of dough. Add water if too dry.
2. Fill the fish with lemon, fennel, herbs, butter and 2 pinches of salt.
3. on a baking tray, spread the salt crust and make a bed from fennel and lemon. Cover with the rest of salt and press firmly.
4. Bake at 200°C for 45 minutes.