Hapanvelli (finnish lit. 'sour gruel') is a traditional south-eastern finnish dish that resembles pea soup but has a more sour flavour. it takes roughly an hour to prepare hapanvelli, which is made from a rye sourdough starter, potatoes and peas. it is traditionally served with a pat of butter and cold milk. hapanvelli is a traditional dish of the virolahti municipality which has the annual summertime virolahti week (virolahti-viikko) during which hapanvelli is sold. there is also a contest during virolahti week in which the best cook gets the title of miss hapanvelli (hapanvellimissi).

Source: Wikipedia