Step 1 – Marinate fish in oblong tray with lemon, garlic, salt and pepper. Cover and refrigerate for at least 1 hour.
Step 2 – Preheat oven to medium (180ºC / 350ºF).
Step 3 – Layer the bottom of a baking tray with onion. Place the marinated fish on top. Cover with cheese and tomato slices, oregano and sausage pieces.
Step 4 – Bake for 25 to 30 minutes. After 20 minutes, pour wine over fish and finish cooking.