Peel onions and cut them into rings. Fry in 2 tablespoons of hot fat in a pot until golden brown. Take out half and put aside. Add the sauerkraut to the pot and steam for about 5 minutes
Boil 600 ml of salted water. Remove from the stove. Add milk, puree and
Stir in 1 tablespoon of fat. Stir again after 1 minute, season to taste. Pour into a greased casserole dish
Wash the chives, cut into small rolls and, except for 1 tbsp, fold into the sauerkraut. Season to taste with pepper and salt if necessary. Spread on the ham slices, roll up loosely and lay on the puree
Grate the cheese and sprinkle over it. Spread the remaining onion rings over it. Gratinate in the preheated oven (electric cooker: 225 °C/circulating air: 200 °C/gas: level 4) for 8-10 minutes. Sprinkle with remaining chives
Drink: cold beer