Peel and chop the onions. Peel and finely chop the garlic. Clean, wash and halve the tomatoes. Heat 5 tablespoons of oil in a pan. Add the tomato halves with the cut surface facing down.
Let them braise at low heat for about 20 minutes. While doing so, move the tomatoes slightly several times with a spatula. Season with salt and pepper 5 minutes before the end of the cooking time. Add onions and garlic. In the meantime, wash the fish thoroughly and pat dry with kitchen paper. Season with salt, pepper and lemon juice. Place the fish on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ gas: level 3) for 15-20 minutes. In the meantime, wash the thyme, dab dry and pluck the leaves from the stalks. Pour 3/4 of the thyme over the fish 5 minutes before the end of the baking time and sprinkle with remaining oil. Arrange the fish on a plate.
Place the fish on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ gas: level 3) for 15-20 minutes. In the meantime, wash the thyme, dab dry and pluck the leaves from the stalks. Pour 3/4 of the thyme over the fish 5 minutes before the end of the baking time and sprinkle with remaining oil. Arrange the fish on a plate. Serve with the remaining thyme and garnished with oregano and basil to taste. Serve with extra braised tomatoes. Serve with Prosecco