Preheat the Oven
Preheat your oven to 400°F (200°C).
Prepare the Fish
Rinse the fish under cold water and pat it dry with paper towels.
If desired, stuff the cavity of the fish with lemon slices and fresh herbs. This adds a wonderful aroma and flavor to the fish as it cooks.
Mix the Salt and Egg Whites (Optional)
In a mixing bowl, combine the coarse sea salt with the egg whites (if using). The egg whites help to bind the salt together, creating a firmer crust. Mix well until the salt resembles wet sand.
Create the Salt Bed
On a baking tray lined with parchment paper, spread a thin layer of the salt mixture (about 1 inch thick). This serves as the base for the fish.
Place the Fish
Lay the prepared fish on top of the salt bed. Make sure it’s centered and straight.
Cover the Fish
Using the remaining salt mixture, completely cover the fish, ensuring it's fully encased. This creates a seal that keeps the moisture in.
Bake
Place the baking tray in the preheated oven and bake for 30-40 minutes, depending on the size of the fish. As a rule of thumb, bake for about 10 minutes per inch of thickness.
Rest
Once cooked, remove the tray from the oven and let it rest for about 10 minutes. This allows the salt to cool slightly and makes it easier to crack open.
Serve
Using a fish spatula, gently break open the salt crust. The fish will be incredibly moist and flavorful. Serve with a drizzle of olive oil, fresh lemon juice, and a sprinkle of fresh herbs, if desired.