This appetizing recipe includes a smart technique for infusing fish with more flavor: Use a sharp knife to make slits at regular intervals all along the top, then season with salt and pepper and tuck sausage pieces into each slit. The fish is also cooked on top a layer of sliced onions, tomatoes, and crushed whole garlic cloves (left unpeeled, so you can pop out the soft cloves for spreading on bread). Basting the fish with white wine halfway through will also help.