One of Groningen's peculiar food specialities is Scottish eggs, locally called Grunse eitjes. They're basically hard boiled eggs that have been fried with a spicy layer of potato or minced meat. Once these were luxurious snacks only prepared for picnics, but now they're in every supermarket and make for excellent snacks when you're wandering around the city. Look for them at the coin-operated automatiek snack bars. We think the version with meat is a little disappointing, so we recommend you stick with the potato variety, which of course is also suitable for vegetarians.