Cheese

Cheese was a type of dairy product that was made mostly from milk. Cheese could come in many different shapes and flavours and was used as an ingredient in many foods.

It was an ingredient in lasagna. (PROSE: Stop, Thief!)

Cheese apparently existed on Alzarius, but not on the nearby "vampire planet" also in E-Space. (TV: State of Decay)

While hiding in the Doctor's TARDIS, Klov Dreb Fotch Passameer Day Slitheen III stole, among other food, cheese sandwiches. (COMIC: Who Ate All the Biscuits?)

Rats were associated with cheese. While using a newsreader as a mouthpiece, Miss Kizlet remarked that her human prey homed in on Wi-Fi like rats sniffing cheese. (TV: The Bells of Saint John)

During the Feast of Omega, a Fortean Flicker turned all the candles into soft cheese. There was a smell of burning dairy products everywhere. (PROSE: Happy Endings)

The Dryrth used cheese as a currency. (COMIC: The Lunar Strangers)

Lake 2 was allergic to cheese, unlike his previous incarnation. (AUDIO: The Lady in the Lake)

Kronkburgers with cheese were served on Satellite Five in the year 200,000. (TV: The Long Game)

Cheese and onion was a flavour of crisps. (PROSE: Citation Needed)

A bus in Montgomery in 1955 had advertisements for cottage cheese. (TV: Rosa)

The Doctor
The Eleventh Doctor claimed to have a doctorate in cheesemaking, albeit "only the stinky, blue kind". (TV: The God Complex, PROSE: Shroud of Sorrow)

The Third Doctor ate a plate full of cheese sandwiches intended for Jo Grant, leaving her with only the lettuce garnish. (TV: The Sea Devils)

The Third Doctor ate gorgonzola while at Auderly House and encouraged Jo Grant to do likewise. (TV: Day of the Daleks)

The Eleventh Doctor used cheese when making himself and Craig Owens an omelette. Craig remarked that it was the most enjoyable thing he had ever tasted. (TV: The Lodger)

The Doctor's TARDIS contained a cheese factory. (COMIC: The Adventures of Strax & the Time Shark)

Other references
According to Jack Harkness, "cheesy" was early 21st century slang. When asked, Mickey Smith reaffirmed that it was bad. (TV: Boom Town)

Jack himself was later described by Ryan Sinclair as being "kind of cheesy", with Yasmin Khan adding that it was a "good cheesy". (TV: Fugitive of the Judoon)

Luke Smith often used "milky" instead, much to Clyde Langer's annoyance. (TV: Secrets of the Stars)