Toast

Toast was bread that had been browned by exposure to heat. People used the expression "warm as toast" to imply that they were very warm. (TV: The Tenth Planet)

One of the three universal constants was toast always falling butter-side down, along with Planck's quantum of action and the reaction of someone entering the TARDIS for the first time. (PROSE: The Secret in Vault 13) Indeed, on 11 June 2022, the reader of a guide for time travellers dropped their breakfast and the toast landed butter-side down. The author noted this as a fixed point in time and warned the reader to not attempt to avert it or they could destroy the universe. (PROSE: )

Whilst in Northumbria in 1066, the First Monk offered his prisoner, the First Doctor, toast, bacon, eggs, and tea for breakfast. (TV: "The Meddling Monk")

Walker ordered a breakfast of eggs, bacon, toast, coffee, and rough-cut marmalade. (TV: The Sea Devils)

When Jo Grant brought a Micro Servo Robot into the TARDIS, it connected itself to the computer and began transmitting adverts. One of these adverts had the Doctor's food machine produce toast with written adverts on it. (AUDIO: Pop-Up)

Ace ordered toast in 1963 from a diner during a Dalek invasion. (TV: Remembrance of the Daleks)

In 1951, the Seventh Doctor and Ace had toast, coffee, bacon, eggs, and kedgeree for breakfast. (PROSE: Timewyrm: Exodus)

In the early 21st century, the Tenth Doctor visited Mickey Smith's apartment for a bite of toast, but ended up staying there when the TARDIS jumped a time track. (COMIC: The Lodger)

While at the grand opening of the Hirnaltaan Tower, the Tenth Doctor noticed the smell of toast from the robot chefs. (COMIC: Night of the Burnt Toast)

The Eleventh Doctor blamed Rory Williams getting toast crumbs on the TARDIS console for their not arriving in Mexico. (TV: A Town Called Mercy)

The Twelfth Doctor remarked the he and Clara Oswald were almost "turned into toast" by an Aaraanandal slime beast. (PROSE: When the Wolves Came)

Ruth made her self buttered toast for her breakfast on her birthday. (TV: Fugitive of the Judoon)

Opinions concerning toast
The Seventh Doctor told Ace that he hated burnt toast. (TV: Ghost Light)

The Ninth Doctor, shortly after meeting Rose Tyler, told her to have her "lovely beans on toast". (TV: Rose) The Tenth Doctor said this to her again after his regeneration. (TV: The Christmas Invasion)

Production of toast
The Doctor tried to make toast, but accidentally burned it. (PROSE: Cat's Cradle: Time's Crucible)

The Doctor once burned toast so badly that he had to open the TARDIS doors. (COMIC: The Old Kings of Skarab)

The Tenth Doctor helped Layla make toast with his sonic screwdriver. (AUDIO: Dead Air)

Milo Clancey tried to make toast for his breakfast, but his solar toaster broke down. (TV: The Space Pirates)

Birdie made large stacks of toast for breakfast after teaching himself how. (TV: Mutant Copper)