How To Make and Use Caramelized Onions (The Pro Method)

Let’s be clear. There is a difference between meltingly soft, slow-caramelized onions and grilled onions. If you think a caramelized onion is basically a hunk of raw onion with some char on the edges like you might find in a nasty Panda Express mall stirfry, then you are in for a very pleasant surprise.


True, slow caramelized onions take time, but they aren’t hard. The trick is to cook lightly salted, sliced onions in a tall pot on moderate heat so that they release their moisture before they begin to brown. Only after the onions throw off their moisture and make a kind of soup do you increase the heat and start the onions browning.

Because this process takes awhile, I like to make a big batch of caramelized onions in the winter when it’s cold and I’m happy to stay inside. I spend several hours futzing on various kitchen projects, stirring my multitude of pots like a crazy alchemist, and come away with little golden jars of onions.

How To Make Caramelized Onions – The Pro Method

Start with a lot of onions – this batch used 8 pounds before peeling, or about 7 pounds after. You will wind up with about a cup of caramelized onions for each pound of prepared onion you start with.

Peel, core and slice your onions in half. Slice them in a food processor fitted with a 4 mm slicer blade.

Try to keep the onion positioned so that it is sliced go from root-to-stem, not from edge-to-edge. If all your slices look like half-circles, you’re slicing the wrong way. You can also slice these onions by hand, if you have an extra seventeen hours to kill.

Get a large, tall stockpot and coat the bottom with olive oil. As your food processor fills up, dump the sliced onions into the stockpot. Sprinkle each onion layer with salt as you add it, and maybe get in there and toss the onions a bit with the salt if you want.

Caramelized Onions

Your onions will probably fill your stockpot. Mine did. That’s good – you want quite a few jars to show for your effort when this is all said and done.

Turn the heat to medium-low and put a lid on your pot. Cook the onions covered until they collapse and throw off a lot of moisture. Every fifteen minutes or so stir the onions to ensure the bottom layer doesn’t start to brown.

When the onions look like a thick onion soup, remove the lid and start cooking the onions lid-off, stirring occasionally. Add in your tied bouquet of fresh thyme and push it down into the onion liquid. Tie that thing tight! Most of the leaves will fall off into the onions, which is good, and the string will let you fish out the twigs easily.

Caramelized Onions

After another hour or two the onions will have lost their soupy look and will be nicely, uniformly golden brown. They will hold a mound when you spoon some up. At this point, add in the wine, vinegar and sugar and stir. Increase the heat to medium or medium-high depending on your stove and stir frequently – you don’t want any scorching!

Keep cooking down the onions until they are a thick mass of caramel-colored jam, and look moist and glossy but not at all soupy.

Taste the caramelized onions, adjust seasoning as needed and transfer to half-pint jars. Keep refrigerated for up to a week, or freeze for 3-6 months.

Caramelized Onions

Printable Recipe for Caramelized Onions

The Best Caramelized Onions
Serves: 7 half-pint jars
  • 8 lbs yellow onions
  • 3-4 tablespoons olive oil
  • 1 tablespoon Kosher salt.
  • 6-10 sprigs fresh thyme, tied in a tight bundle with kitchen string
  • ½ cup red wine vinegar
  • ½ cup dry red wine
  • ½ cup sugar
  • Salt and freshly ground black pepper, to taste.
  1. Peel, core and halve onions.
  2. Slice onions in a food processor fitted with a 4 mm slicing disk.
  3. Coat the bottom of a large, tall stockpot with a thin layer of olive oil.
  4. Transfer the sliced onions to the stockpot. As you add the onions, sprinkle layers of onions with the Kosher salt to help draw out the moisture from the onions.
  5. When all the onions are sliced, turn the heat under the stockpot to medium low and cook, covered, until the onions start to release their moisture. Periodically lift the lid and stir the onions to ensure the onions do not brown or stick.
  6. After an hour or so, the onions should have deflated and reduced by about a third.
  7. When the level of moisture in the pot is about equal with the top of the onions, remove the lid and add the tied bundle of thyme to the pot. Use your spoon to push it into the mass on onions. Leave the lid off and allow the onions to slowly reduce and caramelize. This can take several hours. Adjust heat as needed and stir periodically so the onions do not burn but continue to darken. The entire mass of onions should slowly and uniformly take on color, getting progressively darker as the onions reduce.
  8. When the onions are reduced by half or more, are no longer soupy, have taken on a light golden color and mound up when lifted with a spoon, add in the red wine vinegar, red wine and sugar.
  9. Increase the heat to medium and finish caramelizing the onions. Stir often - at this stage the onions can scorch quickly - and cook until the onions are a rich dark caramel color and look moist but not at all liquidy.
  10. Remove from heat, fish out the bunch of thyme and discard, and adjust seasoning with salt and pepper.
  11. Ladle the caramelized onions into clean half-pint jars. Lid and transfer to the refrigerator.
  12. Onions will keep for a week or so in the fridge, and for 3-6 months frozen.


How To Use Caramelized Onions

How can’t you use these caramelized onions is probably a better question.

True caramelized onions are a gossamer balance of sweet and savory and they play well with others in the kitchen. They are a sophisticated base for soups or sauces or dips, a filling for savory tarts and quiche, a topping for pizza or egg scrambles, a side for charcuterie and cheese plates – these onions are infinitely useful in the kitchen.

Steak with Caramelized Onions

In the picture above, I used them as-is to top a steak. They are excellent with meat of all kinds. Saute some apple and add a jar of these onions and a splash of maple syrup and you have a quick and delicious sauce for pork loin. Top a fillet of halibut or salmon with a coating of caramelized onion and bake until just cooked through. Easy, moist baked fish. Combine a jar with a bit of stock and a splash heavy cream and now you have a creamy onion sauce for roast chicken.

Thin down a jar with beef stock for nearly instant French Onion Soup – add a toasted crust of bread and Gruyere cheese for the best winter soup in town.

Make a winter pizza with pear, caramelized onions and chopped walnuts. Smash a jar together with goat cheese and warm in the oven for a delicious spread to serve with baguette. Make a caramelized onion frittata or quiche.

With a pie crust I had in the freezer, a jar of caramelized onions and a handful of blue cheese I made this easy savory onion galette that Homebrew Husband declared the most delicious thing he’s ever eaten. (See also: Drunken Pie Crust: The Secret to Great Pie.)

Caramelized Onion GaletteIMG_6616

So really, the possibilities are endless.

Do you make caramelized onions?


  1. Homebrew Husband says

    Its not hyperbole when Erica says I declared this that onion galette the Most Delicious Thing Ever. I even cried a little bit, with joy, while eating it.

  2. says

    I absolutely love caramelized onions on pizza – which reminds me that I’m due to make some more. :)

    PS – I think you forgot the “onions” in your ingredient list. Oops!

  3. says

    All I want is that galette. I’ve never made a big batch of onions like that, but now it will be happening this week! I love the idea of having them freezer ready. I happily eat them with just about everything, too.

  4. Liz says

    Synchronicity … only this afternoon I was pondering a mountain of onions and wondering what to do with them … problem solved! Thank you.

  5. Dan says

    Are these can-able? I assume a pressure canner would be required. Any ideas on time/pressure? Between the 1/2 pig and 1/8 beef, my freezer space is very limited.

    • Melissa C. says

      I’m not sure about pressure canning, but storing them, pre-measured, into flattened plastic bags might save you some space…assuming you’re not anti-plastic.

    • says

      I can’t recommend pressure canning because there is not, as far as I know, an approved method for canning onions of this density and which include fat. Online, I’m seeing non-approved recipes saying 70 minutes at 10 psi, which is more than corn or mushrooms, but not quite as much as animal proteins.

  6. Barb says

    OMG! That stupid little sandwhich I brought for lunch today is so NOT going to hit the spot after reading this blog. Checking my calendar now to see if Saturday or Sunday is going to be better day to babysit onions.

  7. Vanessa P. says

    Do you have any guidance on how much space to leave in the jar if you’re going to freeze it? I don’t want exploded jars of onions in the freezer!

  8. Lauren says

    Making caramelized onions ahead of time? MIND BLOWN!!!
    Personally I love a good pizza with ground beef, caramelized onions, and sharp white cheddar with optional fresh basil topping (depending on the season).
    Thanks for the tips! ~ L

  9. Beka says

    This is fabulous! I just made French onion soup last night, but I’d never thought of carmelizing extra onions to freeze. I’m gonna try this soon.

    • growerjenn says

      Erica – feel free to remove my post — I haven’t done this and after you mentioned the fat content, now I will have to do some more research

  10. Victoria says

    Great idea…..caramelized onions go with so many foods. They also are wonderful in an peach apricot chutney as a side with various meats. Thanks E.

  11. says

    Love this! I’ve seen far too many recipes from sites that should know better that talk about “caramelizing” onions in 45 mins. HOOEY!!!
    My recipe doesn’t call for quite as much sugar, but then again, I always use sweet Vidalia onions, so that might make a difference.

  12. says

    Huh, interesting – I’ll have to try it this way. I’ve been caramelizing my onions by slow heating on the stovetop without anything (except olive oil and butter). Thanks for the suggestion!

  13. Beth says

    About variety…caramelized onions are best made with regular ( and less expensive ) yellow onions. Vidalias and other very sweet onions don’t actually have a higher sugar content, they just have lower sulphur and are therefore favored for fresh and lightly cooked applications . When cooked at length, they don’t have very complex flavor and are kind of lame. Good ol’ yellows or whites are far tastier caramelized and at a fraction of the cost.
    Also, when I worked in restaurants we usually used sherry instead of wine and sugar. Do normal people keep sherry in the house or is that a Frasier and Niles thing? ( what do I know, I’m a Mormon) I used to know somebody who went to the trouble to properly caramelized onions and then throw in a …wait for it….Boullion Cube….eeewwww

    • says

      Bouillon cube? Yeah, not my style either. These would totally be great with sherry, too. I keep sherry in the house, but then my drinking habits are quite….uh….non Mormon. :) I’ll try it that way too.

  14. says

    The other option is to use a slow cooker. I do this about once a month and it produces great onions without a lot of fuss. Plus, you can put it outside and keep the smell from invading every corner of your home.

  15. Sherwood says

    Would it be reasonable to do the initial processing in a slow cooker? This way you could start a batch before going to work, and have it partially done by the time you got back.

    • says

      I think so – I have heard since publishing this post from several people who do the entire process in their slow cooker, so I think it is a viable alternative.

  16. says

    wowzer, i couldn’t get started on making a batch of these onions fast enough. we love caramelized onions. we grow as many onions as we can and purchase them by the 50lb bag when we find one at our local farm store just so we eat as many onions as we want. we usually make what we “thought” was caramelized onions a couple of times a week as a topping or condiment. these caramelized onions tho are absolutely amazing. in all seriousness. hands down the best ever. and that onion pie thingy – oh yeah, delish is an understatement. erica, thank you very much for rockin my world and sharing onion goodness!

  17. says

    Yo…can I make these with balsamic vinegar instead of the wine. I can’t drink alcohol…and so never have any. I have seen recipes for balsamic caramelized onions, and I’d think it would be about the same, yes ??

    • says

      For sure you can. Won’t be exactly the same but will still be yummy. Instead of this:
      ½ cup red wine vinegar
      ½ cup dry red wine
      ½ cup sugar
      Substitute 1/2 cup balsamic vinegar and 1/4 cup apple cider vinegar or red wine vinegar and adjust to taste, adding some sugar if needed – don’t do balsamic AND the full amount of sugar because it’ll be too sweet probably. Balsamic has a lot of natural sweetness.

  18. says

    Oh my god! Seriously, great recipe!! I did not add the wine (because I drank it all, jk, I didn’t have any haha) and it still turned out great!! My boyfriend loved them!! Thanks for the recipe!!

  19. Elissa says

    Just made several batches of this with our unexpectedly large onion crop – I agree with everyone, it’s fabulous! And very good to see your post for New Years. All the best for 2015.

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