Clean, wash and thinly slice the carrots. Clean, wash and cut the celery into pieces. Wash lemon thoroughly and cut into slices. Heat the oil in a pan, briefly sauté the lemon slices in it, remove. Add carrots and celery to the fat and fry while turning, deglaze with wine and let it braise for about 5 minutes. Season with salt and pepper.
Meanwhile wash the fish, dab dry, cut into four pieces, season with salt and pepper and sprinkle with lemon juice. Put the vegetables in an ovenproof dish, place the fish on top, add butter in flakes and bake in a preheated oven (electric cooker: 200 °C/ gas: level 3) for about 20 minutes. Wash the dill, dab dry and chop except for a little to garnish. Serve the fish platter sprinkled with dill and coloured pepper. Garnish as desired with lemon wheels and dill. Boiled potatoes taste good with it