Heat the oil in a frying pan. Prick the sausages and fry them all around in the hot oil. Take them out.
Wash the marjoram and shake dry, pluck off the leaves and chop finely. Whisk cream and eggs. Stir in marjoram. Season well with salt, pepper and nutmeg.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Grate cheese. Cut the pretzel breadsticks into slices. Cut sausages into slices. Wash, quarter and core apples. Cut apples into thin slices.
Grease a casserole dish. Layer pretzel sticks, sausages and apples in the dish. Pour marjoram cream evenly over it. Sprinkle with cheese. Bake in a hot oven for 35-40 minutes. Sprinkle the nuts over the casserole 10-15 minutes before the end of the baking time.