Pontefract cake

At the successful conclusion of the operation against Winifred Gillyflower, the Eleventh Doctor suggested to Jenny, Strax and Vastra that he have some Pontefract cakes on him. (TV: The Crimson Horror)

Behind the scenes
Unremarked in the episode is the fact that Pontefract cakes aren't cakes at all, but rather a type of liquorice sweet.