Peel onion and cut into thin rings. Clean and wash the cabbage and cut into fine strips. Heat 1 tablespoon of oil in a wide frying pan, fry the onion and cabbage in it over a high heat, turning them over for 3-4 minutes. Season with salt, pepper and nutmeg and remove.
Wipe out the pan, heat another 1 tbsp. of oil in it, dab the steaks dry and fry them for about 1⁄2 minutes on each side. Take out.
Melt 1 tablespoon butter in a frying pan, toss buttons in it over low heat, season with salt and pepper.
Preheat oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer). Layer onion cabbage, steaks and knöpfle in two small portion casseroles. Grate cheese finely. Mix with cream and pour over the casserole. Bake in a hot oven for about 10 minutes. Switch on the oven grill and grill the casseroles for about 5 minutes until crispy. Sprinkle with chives as desired.