Peel and rinse the potatoes and cook in salted water. In the meantime, peel and dice the onions. Dice the bacon. Rinse zucchini, clean, cut lengthwise, scoop out, coarsely chop the insides. Fry bacon, remove from frying pan. Sauté zucchini and half of the onions in the bacon grease. Drain potatoes, press through potato ricer.
Mix potatoes with a quarter of the crème fraîche, egg and zucchini mixture. Add 3/4 of the bacon cubes with a little bit of chervil to the potatoes form, season with nutmeg, salt, pepper. Fill the zucchini halves with it, sprinkle with the remaining bacon. Put the zucchini and the remaining onions in a shallow gratin dish, pour the clear soup over them.
Cook in the oven at 200 °C (gas mark 3) for 20-30 minutes. Keep the zucchini warm. Blend the gravy and add the remaining crème fraîche. Add the sauce thickener and let it bubble up again.
Our tip: Use a bacon with a strong flavor – so you give this dish a special touch!