Sæterrømme is a special rich type of rich Norwegian sour cream, traditionally made at mountain farms. It is akin to crème fraîche so outside of Norway this can serve as a substitute.
Soak the barley in cold water for 12 hours.
Bring the barley and the broth to a boil in a pot, skimming the foam when it boils. Turn down the heat and let the barley simmer for about 45 minutes, until tender, and almost all the broth has cooked away.
Clean the mushrooms and cut them into smaller pieces. Fry them in a pan, adding salt and pepper.
Add the mushrooms to the barley and thicken with grated cheese and rømme so that it gets creamy, á la risotto.
Flavor with salt, pepper and a few drops of vinegar, to get the right balance in the otto.