Bitterballen are Dutch deep-fried, breadcrumbed, meat-filled balls. The filling usually consists of beef, flour, beef broth, and various seasonings. The dish is usually served as a snack at bruin cafes, a popular type of bar in the Netherlands.
Bitterballen are traditionally paired with mustard, french fries, and bittertjes, or Dutch bitters. It is believed that the dish was invented in the 17th century, when the Spaniards occupied the country, and the wife of an Amsterdam pub owner refined and adapted the Spanish version of the dish and served it with beer and jenever.