A rock cake, also called a rock bun, is a small fruit cake with a rough surface resembling a rock.
Rock cakes originated in Great Britain, where they are a traditional teatime treat, but are now popular in many parts of the world. They were promoted by the Ministry of Food during the Second World War since they require fewer eggs and less sugar than ordinary cakes, an important savings in a time of strict rationing. Traditional recipes bulked them with oatmeal, which was more readily available than white flour.
A typical modern recipe for 12 cakes requires about 200 g of flour, 100 g of butter or margarine, 50 g of sugar, 1 beaten egg, 1 teaspoon of baking powder, 2 tablespoons of milk, 150 g of dried fruit such as currants, raisins, candied orange peel, etc., and a pinch of nutmeg and mixed spices. Usually, flour and butter are first mixed until the mixture resembles breadcrumbs; then the other ingredients are added to create a stiff dough, which is dropped from a spoon to a baking tray or roughly formed with two forks. The cakes (optionally sprinkled with sugar and cinnamon) are baked for about 15 minutes at 200 °C, retaining an uneven form and contour.
Variations include the Jamaican rock bun, which is similar but can include grated coconut, and the traditional British rock cake, which contains oatmeal.
Rock cakes are mentioned as an alternative to doughnuts in the 1940 British film Night Train to Munich. They are also a common feature in the popular Harry Potter series of books and films. In the Benny Hill song Ernie (The Fastest Milkman in the West), Ernie is killed by a rock cake below the heart and a pork pie to the face. In the British soap opera EastEnders, rock cakes are stocked in the local cafe, and Tamwar Masood frequently eats them as an alternative to pastries.
Early in The African Queen, Mr. Allnut (Humphrey Bogart) is offered a rock cake while at tea. Detective Alan Grant is offered rock buns in Josephine Tey’s novel, The Daughter of Time. Rock cakes are also referred to in an early scene in the 1939 movie, Goodbye Mr. Chips. Agatha Christie mentions them more than once in her stories and novels, including Three Blind Mice and The Murder at the Vicarage. In Harry Potter and the Philosopher’s Stone, Hagrid serves them at tea to Harry and Ron.