A Norwegian speciality, mysost is a firm, mild tasting whey cheese with a distinctive caramel-like aroma and a golden brown colour. It is made by boiling down whey with milk, cream and other ingredients until a thick brown mass is formed, which is then shaped into blocks of cheese.

Mysost  —  "whey cheese"  —  is also called brunost  —  "brown cheese". Myse is Norwegian for whey.

A traditional Norwegian whey "cheese", prim (see the picture below), is made by boiling down the whey left over from cheese making. Prim has a soft and spreadable, butter-like consistency. The firmer mysost is produced by adding milk or cream in the prim during the cooking process. When the mixture is further heated, the lactose (milk sugar) which it contains begins to caramelize, giving the resulting mass its sweetish-sour caramel flavour, resembling salty cream toffee. This type of whey cheese is said to have first been produced in the Gudbrandsdal valley in southern Norway in the early 1860s.

Picture on right: prim  —  Norwegian soft whey spread.

There are many different varieties of Norwegian whey cheeses, varying in colour and flavour from light to dark brown and from mild tasting to almost burnt caramel flavoured. Cows' or goats' milk is mainly used in producing the cheeses. Some of the best-known brands include Gudbrandsdalsost (in top picture), Norgold and Ski Queen.

Mysost is very popular in Norway where it is eaten typically at breakfast, usually thinly sliced on toast, crispbread or hot waffles. It is also used in cooking, mixed in salads or to flavour various sweet and savoury sauces, dressings, fondues, dipping sauces and desserts.