Preheat the oven to 220 °. Spread an ovenproof dish with olive oil. Place the fish fillet blocks side by side in the dish.
Prepare a batter from finely diced onions, crushed garlic, chopped parsley, breadcrumbs, finely chopped tomato peppers, cheese, white wine, lemon juice, salt, pepper and cayenne pepper. Spread on the fish fillets, sprinkle with flakes of butter and bake everything for 35-40 minutes.
Mashed potatoes and tomato salad go well with this.