Often recipes ask for caramelised onions. What are some good techniques for cooking them this way, as it seems to take a while, and often even if they are on a low heat they can brown a bit too much if they are not stirred continually.

  • My wife does this all the time as a sauce base. About ten minutes of constant stirring on low heat for two big onions.
    – papin
    Jul 21, 2010 at 11:11

6 Answers 6


Low and slow is the only way to go, I'm afraid. You can add some broth and simmer them down (as opposed to just cooking them in oil) but make sure you add little enough that it will all evaporate...Don't want to be pouring off flavor.

  • So if I add a little broth (or just water if I don't want any extra flavour from the broth presumably) then they will still caramelise and they are much less likely burn? Are there any downsides to adding the liquid?
    – Sam Holder
    Jul 20, 2010 at 21:58
  • @Sam Holder: The sugars all come from inside the onion, so they'll caramelize no matter what. Liquids will leech yummy onion-ness from the onion into the liquid, so just boiling them in water is likely to get you yucky onions. Using a flavorful liquid, and evaporating it, you can get the best of both worlds. Jul 21, 2010 at 13:57
  • 2
    I meant can I add a little water (a tablespoon or so) so that the onions are not going to catch and burn, but not so they are boiling in water, and it will evaporate off, but will mean that I don't need to stir constantly and if I take my eye off them for a few minutes they won't be browned, rather then caramelised?
    – Sam Holder
    Jul 21, 2010 at 19:02
  • 1
    Being low and slow you won't worry about burning. When he says low he means lowww. I have found there is a direct correlation between cook time and taste. Longer the better, thus lower and slower the better.
    – Chris
    Aug 28, 2010 at 13:49

In addition to what everyone else has said, you may want to add some salt as the onions caramelize. The salt will help draw out the sugars, and allow them to caramelize more.

Some techniques I've seen also suggest a little sugar to help the caramelizing process... but personally I think that's cheating. That's up to you though.


I think you've answered your own question. Low & slow, with constant stiring. To hot & fast will burn the sugars you are attempting to bring out of the onion.

I don't believe there are alternatives to doing this. But maybe someone will correct me.

  • I'm hoping someone will too :)
    – Sam Holder
    Jul 20, 2010 at 17:23

In a very low effort way you can do it with a crock pot. Put in 2-4oz of butter depening on crock pot size and as many onions as the crock pot will hold. Set it on low. Come back 8 hrs later.


I generally use butter, EarthBalance, or extra virgin olive oil, and lots of time. If I'm in a rush I will sometimes turn the heat up a little, but the that nearly always causes an inconsistent or lower quality result.

Also I find it helpful to separate them onions early in the process. Generally we slice them into rings before cooking. I separate the disks as I place them in the pan. I've found that while this increases the space they require for cooking, it greatly improves the quality of the results (again supports even cooking).


Take a warm pan, add oil, add onions. The higher the temperature of the pan, to about medium levels, the more frequently the onions need to be stirred in order to not burn them. Lower temperatures take longer to produce the caramelization but mostly give a more uniform result, as one can keep the onions on the heat longer. You'll need to find out what heat works best for you by experimenting a bit. Also different oils make for different flavors, I prefer x virgin olive oil.

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