The Danish national custom for Smørrebrød, which means “buttered bread” is simply an open faced sandwich, eaten with a knife and fork. It’s hard to pronounce in English, but most agree that it’s close to smor-rebrod or smuhr–bruth.
Smørrebrød came into being with the onset of factory production in Denmark; unable to return home for lunch, workers started to bring food with them in the form of these little open faced sandwiches, utilizing leftovers from the previous night’s meal.