The bread's nearly black color and long shelf life both come from the same ingredient — a heavy dose of dark syrup baked right into the rye dough.
Rye flour is mixed with rye malt and dark syrup into a dense, slightly sweet dough, then slow-baked until deeply browned. Archipelago bakeries on Åland sell it sliced, often alongside butter and cheese, as an everyday market staple.
Muikku (Fried Vendace)