A whole kalakukko can stay edible for up to two weeks without refrigeration, which is exactly why loggers and farmers once carried it into the forest as packed lunch.
Small fish like vendace or perch are layered with pork fat inside a thick rye dough, sealed into a loaf, and slow-baked for hours until the crust turns dark and the fish inside steams tender. Kuopio's market hall and bakeries sell it whole or by the slice.
Muikku (Fried Vendace)