The well-known and hearty winter dish of carbonade Flamande or Vlaamse stoverij/stoofvlees was, according to the Belgians, invented by them. The French of course claim that the French equivalent of boeuf Bourguignon was the original. Originally a farmer’s dish from north Europe, ideal for keeping the cold at bay, it’s a rich deeply satisfying plate of caramelized onions and slow-cooked beef. The French use red wine, but in Belgium, the dish is cooked using Belgian beer, particularly Oud Bruin (Old Brown, or Flanders Brown). The beer's secondary fermentation adds a slightly sour flavor and perfectly counteracts the sweetness of the onions. Bread covered in mustard is added and the dish is served with mashed potatoes or frites.
Nearly every Belgian restaurant will have this on their menu, and it’s particularly popular in traditional brasseries. In Brussels go for Le Fin de Siècle at 9 rue des Chartreux where the old wooden floors, tables, and chairs take you back to 19th-century living.