It is whole fish baked under a crust of sea salt. Click here for the recipe. You only need a trusted fish monger and a good sea salt. I went to Capt. Rick at my local green market and bought 2 medium size striped bass. This is why the crust in the picture seems so big: it is 2 fish inside.
What I love about this recipe is that when you break the crust in front of your guests it makes quite a theatrical scene. The crust allows the fish to retain its moisture and the fragrance of the herbs and garlic inside it. I'd like to think that somehow the good minerals from the sea salt get transferred to the fish, too. But I'm not sure.