Originally produced in the Gudbrand valley in Norway, Gjetost is also known as Gudbrandsdalsost. The name also derives from the Norwegian word for goat - Gjet.
The production of Gjetost is unusual in that it's made by heating (and therefore reducing) the leftover whey of cow's and goat's milk until the lactose caramelizes - hence the light brown appearance of the cheese. The mixture is then poured into rectangular molds (or traditional larger round ones) and left to cool. Occasionally, cheeses are made solely from goat's milk, in which case they are known as Ekte or genuine Gjetost.
Flavors of Gjetost resemble a slightly sour but sweet caramel. The texture is smooth and fudge-like.
Since Gjetost has a very low moisture content, it is extremely durable, so much so that traditionally mariners took the cheese with them on long voyages. Contemporary uses include thin-shaven slices accompanied by coffee for breakfast, or as a Christmas time favorite in Norway, where it is eaten with spiced fruit cake.