Clean and cut the leeks and slice the garlics. In a pan add a little virgin olive oil and poach the leek and garlic. Squeeze an orange and save the juice. While the leek and garlic cook, add half a glass of white wine and let it reduce.
Once the wine was reduced, pour the contents of the pan into the container where you had the juice and pass it all through a blender. Add a little of salt.
Wash and cut the fennel in strips. Add a little more oil to the leek and cook the fennel for one or two minutes, but do not let it soften.
Preheat the oven to 200 ° C with both heat up and down. Salt the fish.
In a baking dish pour the virgin olive oil and spread it throughout the base. Place the fish over the oil and coat it so that it becomes impregnated.
Wash and cut the orange into slices (unpeeled) and place it at the base of the baking tin, including under and over the fish. Then spread the fennel over the fish and the orange.
Finally sprinkle the juice you prepared over the fish and place it in the oven with the heat up and down, at 250 °. Cook for 20 minutes or until the flesh of the fish falls off the spine.
Serve hot with some vegetables and a slice of orange. Sprinkle with salt flakes.