A wedding cake was a cake which was traditionally served at a wedding. (TV: Something Borrowed, The Big Bang, PROSE: Happy Endings)
The Third Doctor asked Jo Grant to save him a piece of wedding cake when she announced her upcoming marriage to Clifford Jones. (TV: The Green Death)
At the reception of Donna Noble and Lance Bennett's wedding, an explosion caused by a Roboform Christmas tree caused a male guest to land on the wedding cake. (TV: The Runaway Bride)
As the best man of Gwen Cooper and Rhys Williams' wedding, Banana Boat was to personally check, among other things, the wedding cake. (TV: Something Borrowed)
Hearing Clyde Langer speak with K9 Mark IV, hidden underneath a table, at Sarah Jane Smith and Peter Dalton's wedding, Luke Smith questioned "you brought the dog?", to which Clyde replied "what did you think was under there, the wedding cake?" (TV: The Wedding of Sarah Jane Smith)
At her wedding to the Eleventh Doctor, River Song mourned that there was no wedding cake. After she had confessed this to Jack Harkness, he brought River to the end of the universe and presented her with a cake. She declined to cut it however, content with having her cake intact at the end of all things. (AUDIO: R&J)