A bacon sandwich was a sandwich containing bacon and sometimes a condiment. It was sometimes known as a bacon sarnie.
Ace ordered "four bacon sandwiches and a cup of coffee" whilst in London during the Shoreditch Incident in November 1963. (TV: Remembrance of the Daleks)
Explaining that "hunger looks very like evil from the wrong end of the cutlery", the Twelfth Doctor rhetorically asked Bill Potts if she thought that her bacon sandwich loved her back. (TV: The Pilot)
Bill was eating a bacon sandwich while arguing with the Doctor about Missy. When she said that Missy was a murder, the Doctor asked if she was enjoying her bacon sandwich, going on to point out that it had a "mummy and a daddy" before telling her to "go tell a pig about your moral high ground." (TV: World Enough and Time)
The Fourth Doctor enjoyed "marmalade and bacon in a sandwich squashed together just so" during his stay at Nest Cottage. (AUDIO: The Stuff of Nightmares) Jack Harkness used a time store to save bacon sandwiches for a "year or two." (AUDIO: Golden Age) Rory made Amy a bacon sandwich for her interview with Chrissie Allen. (PROSE: Summer Falls and Other Stories)
Ace liked "bacon sarnies". (PROSE: Timewyrm: Revelation) The Seventh Doctor requested bacon sarnies as his second choice when Ace and Hex went for breakfast. His first request, a cadimonel prusket, couldn't be found in London. (PROSE: Six Impossible Things Before Breakfast)
The Ninth Doctor once offered a bacon sandwich and ketchup to Rose at a cafe. (AUDIO: Retail Therapy)
Susan Foreman liked bacon sandwiches. (AUDIO: Relative Dimensions)