Clean and quarter 200 g mushrooms, fry them briefly in a little butter and season with salt, pepper and paprika. Pour into a bowl. Whisk the milk with the cream, cornstarch, salt and pepper and add to the mushrooms in the bowl. Then add the drained mussels and mix everything well.
Place a mussel and a little mushroom sauce in each of the mussel shells, place the shells on a baking sheet, sprinkle with grated Emmentaler and bake for 10-15 minutes until the cheese turns brown.