Upvote:7
TripAdvisor mentions some vegetarian restaurants in bigger cities like Elbląg, Olsztyn or Mikołajki.
If you go to wilder places and look for small, traditional restaurants, then majority of food would be meat-heavy or at least with meat fat added.
But if you don't mind eating in non-vegetarian place, in every restaurant there will be dishes like dumplings with mushrooms, many vegetable soups etc. Although I'd recommend mentioning you're vegetarian when ordering, otherwise what looks in menu as non-vegetarian meal could be covered with pork rind.
If there's a separate section with vegetarian meals, it'll be probably described as "dania jarskie".