Peel and chop the onion. Peel and slice the garlic. Wash and halve the tomatoes. Clean, clean and halve the mushrooms. Heat 2-3 tablespoons of olive oil in a frying pan, fry the mushrooms in it while turning, add onion and garlic, fry briefly and add the tomatoes.
Briefly braise. Season to taste with salt, pepper and dried herbs. Place one slice of bread in each ovenproof dish (or in a large casserole dish), drizzle with one teaspoon of olive oil per slice and bake in a preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 6 minutes.
Meanwhile, wash the fish, dab dry, cut in half lengthwise, sprinkle with lemon juice and season with salt and pepper. Oil
In the meantime, drain the mozzarrella well in a sieve. Place two pieces of fish on each slice of bread, spread mushroom and tomato vegetables evenly on top, spread mozzarella on top and bake again in a preheated oven (electric cooker: 200
Remove from the oven and serve garnished with some rocket.