Sweetened potato casserole (Finnish imelletty perunalaatikko) is a traditional Finnish dish from Päijät-Häme.

[1] It is prepared by letting puréed potatoes, mixed with wheat flour, stand at a temperature of around 50°C (122°F).

The amylase in the flour will start to break down the potato's starches to shorter carbohydrate chains, that is sugars.

The temperature cannot exceed 75°C (167°F); otherwise, the amylase molecules will break down.

[2] Through this process, the dish gets its distinct sweet flavour; nowadays, however, dark syrup (Finnish: tumma siirappi) can be added to give it sweetness.