Wash the pork tenderloin and pat dry. Cut into slightly thicker slices, season and fry briefly on both sides in a non-stick pan with a little oil. Steam the chopped onion until translucent, then add the cream, mushrooms and processed cheese, season a little, to taste and bring to the boil. Sprinkle everything with grated cheese and bake for 20 minutes at approx. 150C °, without a lid.