Drain the beans. Clean, wash and cut the Chinese cabbage into strips. Peel and wash potatoes and cut or slice them thinly. Layer vegetables and potatoes in flakes in a greased gratin dish
Peel onion and garlic. Chop the onion finely, press the garlic through a garlic press. Wash the sage and chop, except for a few leaves for garnishing. Grate cheese
Mix sour cream, milk, egg, onion, garlic, sage, salt and pepper. Pour over the gratin and
sprinkle with cheese. Spread butter flakes on the gratin and bake in the preheated oven (electric oven: 200 °C/circulating air: 175 °C/gas: level 3) for 45-50 minutes. If necessary, sprinkle with coloured pepper and garnish with sage