“What did the hamburger say when it pleaded ‘not guilty’?”/“I’ve been flamed!”

A hamburger riddle is:
 
Q: What did the hamburger say when it pleaded “not guilty”?
A: “I’ve been flamed!”
 
The hamburger joke has been cited in print since at least 1978.
   
“How did the jury find the hamburger?”/“Grill-ty as charred” is a related hamburger riddle.
   
   
Google Books
One Hundred and One Hamburger Jokes
By Phil Hirsch
New York, NY: Scholastic Book Services
1978
Pg. 93:
What did the hamburger say when it pleaded “not guilty”? “I’ve been flamed!”
   
Twitter
Bollywood Sargam‏
@bollywoodsargam
Burger jokes - 2243 Joke: What did the hamburger say when it pleaded
‘not guilty’?
I’ve been flamed! .... http://bit.ly/19Pc8g
7:09 PM - 10 Aug 2009
 
Twitter
Dutch’s Burgers‏
@DutchsBurgers
What did the Dutch’s hamburger say when it pleaded ‘not guilty’?
I’ve been flamed
5:11 PM - 4 Sep 2009
 
Google Books
The Mammoth Book of Really Silly Jokes
Edited by Geoff Tibballs
London, UK: Constable & Robinson Ltd
2011
Pg. 111:
What did the hamburger say when it pleaded not guilty?
I’ve been flamed!
 
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series
By Frank Paul
BookBaby
2014
Pg. ?:
What did the hamburger say when it pleaded ‘not guilty’?I’ve been flamed!
     
Twitter
Laurel Holden‏
@LaurelFHolden
What did the hamburger say when it pleaded ‘not guilty’? I’ve been flamed!
7:15 AM - 17 May 2017