This classic casserole is one of the most popular Swedish dishes, which is often served for Christmas. It consists of potatoes and sprat fillets—do not mistake these with anchovies as it is suggested in many recipes—which are layered with onions and then doused in cream.

The top of the casserole is occasionally basted in butter and sprinkled with breadcrumbs before it is baked until golden. Although it is believed that this Swedish casserole appeared earlier, the first written recipe under the catching name of Janssons frestelse, translated as Jansson's temptation, appeared in 1940.

Allegedly, the name was inspired by Pelle Janzon, a popular Swedish opera singer. There's also Hansson's temptation, a vegetarian version without the sprats, loved by children, and Karlsson's temptation, in which the sprats are replaced with sautéed ground beef.