Custard pie

A custard pie was a pie filled with custard, which could be considered to be a novelty. While on a planet where reality could be manipulated by imagination, the Eighth Doctor imagined a custard pie gun and used it to rescue Fitz Kreiner. (PROSE: The Crooked World)

References in invalid sources
Shortly after the Twelfth Doctor stepped out of the TARDIS, Krusty the Clown threw a custard pie at the camera, only for it to be licked off by Scooby-Doo. He was surprised when he saw Unikitty jump out of the TARDIS, accidentally landing a pie on his head. He later watched on as a child placed Scooby-Doo and the Ecto-1 onto a LEGO Gateway. (NOTVALID: Endless Awesome)