Prepare the Brussels sprouts (ready to cook, e.g. peel, remove woody parts and dirt) and blanch. Take out two thirds of them, soften the rest.
Mix the potatoes with the blanched Brussels sprouts as well as the strips of ham and place in an ovenproof casserole dish form.
Mash the softened Brussels sprouts with the eggs and the sour half cream and season with salt, pepper and nutmeg (freshly grated). Pour over the gratin and mix lightly.
Mix the ground rye with the Gruyère, the coffee cream and the spices and spread evenly over the gratin.
Meanwhile, bake in the oven at 200 °C for 35 min.
Tip: Always use aromatic spices to refine your dishes!