A rönttönen is a traditional sweet finnish delicacy from kainuu. a small (about the size of the palm of a hand) open faced pie consisting of a crust made of barley or rye dough, filled with a sweetened mashed potato and berry (most often lingonberry) filling.typically, it is served as an accompaniment to a coffee. the kainuun rönttönen has a protected geographical indication under the eu law.
Source: Wikipedia