To peel the skin off the chicken thighs, soak them in plenty of salt water for 4 hours. Peel off the skin and separate the thigh and lower leg at the joint. Fry the well-dried chicken pieces in portions in 220 degrees hot frying oil for about 10 seconds until light brown.
Chop the onion and roast it in a casserole with the sunflower oil. Deglaze with white wine and lemon juice and dissolve the sugar in it. Add the chicken thighs and add enough of the water to cover all parts. Add the bay leaves and celery and let simmer for about 50 minutes without the lid. Turn carefully every now and then.
Strain the broth and pour it back into the pot up to the thighs. Season the broth to taste, add the sage leaves and simmer for another 10 minutes. Transfer to a pan and serve warm with bread. A semi-dry white wine or a cold beer goes well with it.