Grits

Grits were an American food that British Prime Minister Harold Saxon once offered President Arthur Coleman Winters on board the Valiant in lieu of tea. Saxon said he didn't really know what grits were, but he intimated that they might make the American feel more at home. (TV: The Sound of Drums)

Whilst in New Orleans in the early 21st century, the Eighth Doctor chose a restaurant that served deep fried rice cakes, to which he added maple syrup, and ate them with grits. (PROSE: The City of the Dead)

Behind the scenes
In the real world, grits are a staple food of Southern USA. Maple syrup is symbolic of Canada, deep frying of Scotland, and rice of China. The mix of racial stereotypes is likely the joke.