“Grilled cheese” has a spoonerism in “chilled grease.”
     
“JUST before Sunday supper, a Des Moines man asked his daughter if she would like a chilled grease sandwich” was printed in the Des Moines (IA) Tribune on May 13, 1958. “Chilled grease sandwich” was printed in the Victoria (BC) Daily Times on November 19, 1958.
     
”chilled grease sammich A grilled cheese sammich that has either been left out all night or refrigerated turning it into chilled grease” was entered in the Urban Dictionary on February 29, 2008. “If you put a grilled cheese in the fridge for long enough it ends up being some chilled grease” was posted on Reddit—Showerthoughts on November 28, 2018. “What do you call a refrigerated grilled cheese? Chilled Grease” was posted on Reddit—Jokes on November 27, 2019. “What do you call a ‘Grilled Cheese’ after a few days in the fridge? Chilled Grease” was posted on Reddit—Jokes on December 24, 2020.
   
“When grilled cheese gets cold then it’s just chilled grease” was posted on Twitter by Alie on April 22, 2016. “@altonbrown when you let a grilled cheese get cold, does it become a chilled grease” was posted on Twitter by Jonathan Cooper on December 1, 2017. “If you let a grilled cheese get cold it becomes chilled grease” was posted on Reddit—Showerthoughts on January 24, 2022.
 
”#NationalGrilledCheeseDay Grilled cheese > chilled grease” was posted on Twitter by Mike Schultz on April 12, 2018. “grilled cheese > chilled grease” was posted on Twitter by Ninja Sex Party on October 14, 2018.
 
     
Wikipedia: Grilled cheese
A grilled cheese (or toasted sandwich) is a hot sandwich typically prepared by heating one or more slices of cheese between slices of bread, with a cooking fat such as butter, on a frying pan, griddle, or sandwich toaster, until the bread browns and the cheese melts. A grilled cheese may contain ingredients besides the bread and cheese, as long as the latter is the main focus.
         
Newspapers.com
13 May 1958, Des Moines (IA) Tribune, “The Front Row” by Elizabeth Clarkson Zwart, pg. 11, col. 5:
JUST before Sunday supper, a Des Moines man asked his daughter if she would like a chilled grease sandwich.
 
After he got his tongue untwisted, and Rosalie got her appetite back, she accepted the grilled cheese sandwich.
   
Newspapers.com
19 November 1958, Victoria (BC) Daily Times, Monte Roberts column, pg. 23, col. 1:
As it happened to be raining at the time, the ambitious young playwright was prudent enough to take his umbrella with him when he went around the corner to the nearest restaurant, where he enjoyed a chilled grease sandwich.
 
Newspapers.com
17 January 1970, Kingston (ON) Whig-Standard, “Random Rural Review,” pg. 8, cols. 2-3:
NAPANEE—A Napanee man and the waitress in a local restaurant ought to get together. A grilled cheese sandwich fanatic, the man went into the restaurant slightly bleary-eyed recently and ordered a “chilled grease” sandwich. “Toasted or plain?” the girl asked.
 
Newspapers.com
2 July 1978, The Sun (Baltimore, MD), “The National Challenge” by J. Baxter Newgate, pg. D3, col. 3:
“Grilled cheese” becomes “chilled grease”—What you get when you order grilled cheese.
Carl H. Savit, Houston.
 
Google Groups: rec.puzzles
Wanted, spoonerisms!
Ronald Cook
Feb 18, 1991, 7:58:27 PM
I’ve always enjoyed a good slice of chilled grease… oops, grilled cheese…
...Ronny
   
Google Groups: rec.food.cooking
WWT: Karla Faye’s last meal.
Elizabeth & Keith Falkner
Feb 6, 1998, 3:00:00 AM
(...)
My kids used to make themselves grilled cheese sandwiches and have canned sliced peaches for dessert. Of course, in time they started calling it “Chilled Grease Sandwiches with Spiced Leeches for dessert”.
 
NOTHING grosses out a 9 year old…
 
Elizabeth
 
Urban Dictionary
chilled grease sammich
A grilled cheese sammich that has either been left out all night or refrigerated turning it into chilled grease. Delicious if you have any kind of munchies, not if you don’t
“Do you want a taste of this deliciious chilled grease sammich?’
“Thats naasssttyyyy!”
by dabizz February 29, 2008
   
Twitter
The Mike
@TheMike31
Y’know how you know grilled cheese is awesome?  The opposite is chilled grease.  And that’s not awesome.
12:27 AM · Dec 17, 2009·Twitter Web Client
   
Twitter
Tainted Love
@rebeccahate
You probably know that today is National Grilled Cheese Day, but what you DON’T know is that tomorrow is National Chilled Grease Day.
6:02 PM · Apr 12, 2012·Silver Bird
   
Twitter
not ‘i’m a gerbil’
@omnichirper
Grilled cheese sandwich. Chilled grease sandwich
10:24 AM · May 7, 2012·Twitter for BlackBerry®
   
Twitter
Megan
@mekavere
After being refrigerated, grilled cheese sandwiches turn into chilled grease sandwiches. Tip: salsa makes everything better. #LeftoverNight
8:35 PM · Nov 20, 2013·Twitter for Android
   
Twitter
Megan
@mekavere
There’s a reason that my family refers to leftover grilled cheese sandwiches as “chilled grease.”
1:18 PM · Nov 3, 2015·Twitter Web Client
   
Twitter
Alie
@aliekrohnphoto
When grilled cheese gets cold then it’s just chilled grease.
4:22 PM · Apr 22, 2016·Twitter for iPhone
   
Twitter
Marco
@Monomirror
the spoonerism for “grilled cheese” is “chilled grease”. just saying
7:45 PM · Apr 4, 2017·TweetDeck
   
Twitter
Shower Thoughts
@atshower
Given enough time, a Grilled Cheese sandwich becomes a Chilled Grease sandwich.
12:17 PM · Apr 16, 2017·IFTTT
 
Reddit—Shittyaskreddit
Posted by u/kukienboks September 10, 2017
Grilled cheese or chilled grease?
       
Twitter
Jonathan Cooper
@SuperGoodIdea
@altonbrown when you let a grilled cheese get cold, does it become a chilled grease
5:29 PM · Dec 1, 2017·Twitter for Android
   
Twitter
Mike Schultz
@biddy_biddy_bop
#NationalGrilledCheeseDay Grilled cheese > chilled grease
12:43 PM · Apr 12, 2018·Twitter Web Client
 
Twitter 
Ninja Sex Party
@ninjasexparty
grilled cheese > chilled grease
3:10 PM · Oct 14, 2018·Twitter for Advertisers.
 
Reddit—Showerthoughts
Posted by u/jeromeous November 28, 2018
If you put a grilled cheese in the fridge for long enough it ends up being some chilled grease
 
Reddit—Jokes
Posted by u/unitedpeopleevolve November 27, 2019
What do you call a refrigerated grilled cheese?
Chilled Grease
       
Reddit—Dadjokes
Posted by u/unitedpeopleevolve December 28, 2019
What do you call a refrigerated grilled cheese?
Chilled grease!
     
Twitter
kenny ♡’s lex
@luviebaybie
what is the opposite of a grilled cheese you ask???
chilled grease.
9:23 PM · Dec 19, 2020·Twitter for iPhone
 
Reddit—Jokes
Posted by u/maltedbacon December 24, 2020
What do you call a “Grilled Cheese” after a few days in the fridge?
Chilled Grease
 
Reddit—Showerthoughts
Posted by u/Agar4life January 24, 2022
If you let a grilled cheese get cold it becomes chilled grease