Mix flour, eggs, 1 teaspoon salt, nutmeg and mineral water to a smooth, thick dough. Let dough rest for about 1 1/2 hours
Clean, wash and drain the lamb's lettuce. Peel onion and cut into fine rings. Put 3-4 lamb's lettuce rosettes together with 2-3 medium sized onion rings to form 4 "bouquets", chill. Mix vinegar and mustard, season with salt, pepper and sugar, fold in oil
Mix lemon juice with approx. 1 litre of water. Rub the quince fluff with a damp tea towel. Peel and quarter the quinces, cut out the core. Cut the flesh into thin slices and put them into the lemon water. Cut open the vanilla pod and scrape out the pulp. Cut the pod into small pieces. Melt 25 g butter in a pot. Let the quinces drip off a little, fry them with vanilla pulp and pod in the hot butter. Add 2 tbsp. sugar, allow to caramelise briefly. Add apple juice, cover and stew for about 25 minutes
Wash meat, dab dry, cut skin several times. Heat a pan without fat. First roast duck breast on the skin side for 5-6 minutes, then continue roasting for about 1 minute on the meat side. Season the meat with salt and pepper, place on a baking tray. Cook in the preheated oven (electric cooker: 100 °C/ convection oven: 75 °C/ gas: not suitable) for approx. 30 minutes in medium heat. Mix starch with a little water, thicken quince stock with it, season with pepper
Brown the hazelnuts in a pan without fat, remove them. Boil up plenty of salted water. Press or grate 1/3 of the spaetzle dough directly into the boiling water using a spaetzle press or spaetzle grater. Bring to the boil and simmer until the spaetzle rise to the surface of the water. Lift out the spaetzle with a skimmer, put it into a sieve, quench and drain well. Process the remaining dough in 2-3 portions in the same way. Take out the meat, wrap it in foil and let it rest in a warm place
Heat 25 g butter in a large frying pan, add the spaetzle, heat while turning and sprinkle with hazelnuts. If necessary, reheat quinces again. Remove the meat from the foil, cut into slices, arrange with spaetzle and quince vegetables. Dip the salad bouquets in the vinaigrette and serve as well. Mix the rest of the lamb's lettuce, onion rings and vinaigrette and add