“What’s the difference between a candle and a curry?”/“A candle only burns at one end.”

A curry riddle is:
 
Q: What’s the difference between a candle and a curry?
A: A candle only burns at one end.
 
The joke has been cited in print since at least 1997.
 
         
23 July 1997, The Mirror (London, UK), “Questions and Answers: Stacey Young,” pg. 5:
Tell us an awful joke: Q: What’s the difference between a candle and a curry? A: A candle only burns at one end.
       
Twitter
iainwp
@iainwp
Replying to @GreenJimll
@GreenJimll what’s the difference between an over-chillied curry and a candle?  a candle only burns at one end #theoldonesarethebest
2:48 AM - 7 Jun 2012
   
Twitter
John Brookfield
@MeltHell
THE DIFFERENCE BETWEEN A VINDALOO
CURRY AND A CANDLE IS THAT A CANDLE ONLY BURNS AT ONE END.
.... http://tinyurl.com/9bu9j43  #extremely
7:03 PM - 10 Oct 2012
   
Twitter
Ben Smith
@BenISmith94
A curry is like a candle stick, smells nice and colourful at one end and burns like hell at the other
5:41 PM - 21 May 2013
   
Twitter
Shit Jokes
@ShitJokes
What’s the difference between a candle and a curry?
A candle only burns at one end.
1:30 PM - 2 Nov 2015
 
Google Groups: FatBoysinPortugal
AGM - Dec 4th
Steve McCarthy
11/10/17
(...)
What’s the difference between a candle and a curry?
 
A candle only burns at one end.
 
The Scottish Sun
4 March 2018, The Sun (London, UK), “Come on down to Punjabi… the spice is right” by Tom Cowan, pg. 34:
I didn’t realise just HOW spicy it was until precisely 3.17am the following morning … What’s the difference between a candle and a curry?
 
That’s right — a candle only burns at one end…
 
Twitter
Dad’s Puns
@DadsPuns
What’s the difference between a candle and a curry?
A candle only burns at one end.
5:04 PM - 30 Jun 2018