Gjetost is a Norwegian cheese that is made from whey. It it cooked slowly until it is reduced in volume and caramelized and almost fudge-like. I have never heard of this cheese but it was discussed in a website comment and since I have the whey I decided to give it a try. . I actually made this cheese and took the photos the next day after I made the ricotta. It was an interesting process. It took longer to reduce down and get thick than the recipe suggested it would so my simmer must have been lower. It did eventually get thick and caramel colored. It had a interesting flavor.