I learned this at Wikipedia:

Groaty pudding (also known as Groaty Dick) is a traditional dish from the Black Country in England. It is made from soaked groats, beef, leeks, onion and beef stock which are baked together at a moderate temperature of approximately 150°C (300°F) for up to 16 hours. In the Black Country it is traditional to eat groaty pudding on Guy Fawkes Night.