Rinse lenses. Peel onion. Dice onion and bacon. Heat the oil in a large pot. Brown the bacon in it, fry the onion. Add lentils, bay leaf and approx. 1 1⁄4 l water. Bring to the boil, cover and simmer for about 30 minutes.
In the meantime, peel or clean the soup greens, wash and cut into fine cubes. Add the stock to the lentils and simmer covered for about 15 minutes. Cook the dried spaetzle in plenty of boiling salted water for about 16 minutes.
Heat the fat in a small pan and roast the flour in it until golden brown. Stir in some lentil stock and then stir into the lentils. Simmer for about 3 minutes. Season with salt, pepper, vinegar and sugar.
Place the sausages on the lentils and heat.
Wash and chop the parsley. Drain the spaetzle. Arrange everything and sprinkle with parsley.
Drink tip: Pinot Gris, e.g. Verrenberger Lindelberg Kabinett trocken from the Hohenlohe eG winery.