How to Make Caramelized Onions in the Microwave

How to Make Caramelized Onions in the Microwave

Thoroughly caramelizing onions, that is removing most of their moisture and converting the natural sugar to mahogany-dark, candy-like goodness, (not to mention the conversion of amino acids to brown deliciousness via the Maillard reactions), can be achieved on the cook-top or even in the oven. But doing so requires vigilance, careful heat control and a heck of a lot of stirring.

This method requires a glass bowl and a microwave oven. So …

Write a review
  1. 4 large yellow onions (enough for 2 pounds), sliced thin
  2. 1 tablespoon dark brown sugar*
  3. 1 tablespoon butter
  4. 1 teaspoon kosher salt
  5. 1/4 teaspoon baking soda**
  1. Peel onions and slice thin (3mm) on a mandolin, or quarter and run through slicing blade of a food processor. (I personally prefer the ceramic blade, hand-held mandolin by Kyocera and no, they don’t pay me to say that.)
  2. Place half the onions in a large glass mixing bowl and toss with half the salt. Add the rest of the onions and sprinkle with the remaining salt. (Although salt will certainly enhance the flavor of the final result, it’s being added here for it’s ability to pull moisture out of the onions.)
  3. Cover tightly with plastic wrap and microwave for 10 minutes.
  4. Uncover (carefully … steam hurts) and drain to pour off any excess moisture. Stir in the butter, baking soda and brown sugar.
  5. Microwave uncovered for 15 minutes.
  6. Stir thoroughly then drain excess liquid again.
  7. Microwave 15-20 minutes more at 3 minute intervals, stirring thoroughly after each until the desired level of brownness is achieved.
  1. NOTE: All use of microwave is at high-power only.
  2. * Although the onion will probably be sweet enough on their own, I like the complexity of the flavor that the molasses in the brown sugar adds.
  3. ** Adding even a small amount of baking soda increases the pH of the onions, which promotes browning. It’s the same reason pretzels are dipped in a lye solution before baking.
So now that you have caramelized onions …

1. Add them to a frittata

2. Top crostini with onions and goat cheese or something stronger like gorgonzola

3. Take finished onions and shredded Gruyere and toast until melted (photo below)

Caramelized Onions and Gruyere Toast

Recipe and images © Alton Brown, 2015.


Add yours
  1. 1
    Jose Albaine

    I love how food can be micromanaged to the point of absolute control. I caramelize my onions on the stove, with baking soda as well, no salt and a bit of butter. They will break down pretty fast, but here’s the trick to prevent burning before they are ready: when the moisture is about to dry out (no water means carbonization happens), add a sprinkle of water, and keep stirring. Water buys you time, and time and movement is all you need to get to that delicious dark brown flavor. When you get to the color intensity that you want, that last splash of water, dissolve some salt in it before adding it (flavor, and i find it gets rid of the alkaline taste of baking soda, if you put too much). The butter in the beginning will make it silky, and it will have the consistency of spreadable jam. This thing is food gold, i try to always keep a quart of it in the fridge, and i add it to anything i cook. It pretty much makes perfect instant french onion soup, if you have some nice beef stock or broth, and you add some fine sliced shallots for texture.

  2. 2

    some people are microwave cooks, some are old fashioned cooks, some are both, any method that works for you are the best. it is great we have all these ideas out there to help us. keep up the good work and ideas.

  3. 3
    Ashley B.C.

    Love, love, love it! I’ve spent many an hour caramelizing onions in a pan the #oldschool way, but since it can be done in the microwave with less attention and exercise (haha), I’m game! In all fairness, I’ve done both microwave caramelized onion and slow-cooker caramelized onions. I always find that while the slow cooker is super easy, if you want true caramelized onions, at some point your going to have to get the moisture out by human intervention and not purely by evaporation….Maybe it’s because my slow cooker has a super gasket seal or I’m just impatient. All in all, my go to is the microwave. Thanks AB!


  4. 4

    I just tried this and I got the “staying yellow and getting mushy” that a couple other people have mentioned. That being said, it tastes good, just not quite caramelized. I’m speculating it’s because I didn’t pour off enough liquid after that second microwaving. So I will try it again in the interests of science. 🙂

  5. 5
    Kathy T.

    I personally LOVE reading all the comments, critiques and suggestions. It can be very instructive and inspiring sometimes. And, as Viola on July 22, 2015 stated, there are situations when a microwave might be the best answer. I think that I will try Alton’s recipe but in the crockpot and see what happens!

  6. 7

    Regardless of which method may be “better” it’s good to know that it’s possible in a microwave. What if all your burners are in use? What if the gas lines are being worked on in the neighborhood? What if you live in a studio apartment w/o a full kitchen? There are any number of reasons one might want to use a microwave and I’m glad to know this works.

  7. 9

    Started out well, but burned them black in the second cooking…. should NOT have stepped away! Will try again and watch them closely!

  8. 12

    Just tried this and it worked perfectly. I’ve never managed to do this well on the stove top as even at low (1) they always seemed to burn. Thanks to Mr. Brown I’ll now have caramelized onions whenever I want with no burnt bitterness!

  9. 13

    I was surprised how good these were, so glad it worked. I teach a life-skills class for kids aging out of foster care and am always glad to find micro wave recipes for real food.

  10. 15

    Not a good product. Onions were mushy, yellowish, and lost their substance. After sitting, they were gummy little clumps. I gave up after 8 3-minute intervals. I would call this a failed recipe and a waste of onions.

  11. 18

    Dear Alton, thanks for the microwave recipe for microwaved onions, it is great and DOES NOT take time after you adjust procedure for your MW oven Microwaves are programmable. Prepare your onions. Start microwaving at high power for about 15 minutes. Then set the lowest power for 30 minute. Watch your onions… Write down optimal procedure for your microwave for future.

  12. 21

    I appreciate the creativity, but by my math it takes at least 40 minutes to do it in the microwave, and possibly longer. I would opt for caramelizing my onions the old fashioned way… vidalias in an iron skillet with and butter and salt. It really doesn’t take much longer and it’s a low maintenance task you can easily do whilst doing other things. Don’t get me wrong, Alton is a genius. His guacamole recipe alone puts him on my all-time good guys list. Just because you can do this in a microwave, doesn’t mean you should.

  13. 24
    Cathy Nordberg

    I work for bakery in Eureka Springs, Ar. And I make a caramelized onion Quiche with bacon that is so tasty. I am known as the Quiche Queen!

  14. 26
    Jolene L.

    I use caramelized onions with pierogi with some sour cream and a touch (pretty much for color) of parsley.
    I like the idea of having several cups of the onions at a time for other dishes so being able to freeze them is fantastic.

  15. 27
    Leslie Holland

    My husband is deathly allergic to the enzymes in raw onions (causes anaphylaxis). He can only eat deeply caramelized onions, once the enzymes have converted to sugar. This recipe will make him so happy! Thank you!

  16. 28
    Kay B

    The even easier way to caramelize onions: slice all the onions you can cram in your slow cooker. Sprinkle with a teaspoon or two of salt and put a stick of butter on top. Take your slow cooker outside on your back porch or carport (this stuff will smell STRONG, I tell you), turn it on low, and go away for 18 hours.

    This will make about four cups of caramelized onions. I put them in plastic baggies in 1/2 cup portions and freeze them; then they’re ready for anything I want to do with them.

  17. 30

    AB I cannot believe I am saying this …. It even sounds blashphomous for me to disagree with anything you say my whole family calls you my fav celeb crush since I always quote and praise you

  18. 31

    One of the pains in carmelizing onions the traditional way is that you can never get more than 5ft from the frying pan because you have to stir them constantly. This constant stirring is even more critical once the onions start to carmelize ; it’s very easy to burn the onions if you step away from the pan for more than 3 minutes.

    The advantage I see with this method is that there is little to no effort required for the first 25 minutes of cooking. After that, yes you are stirring them every three minutes, but if the phone rings or the kids start fighting you can step away because at the end of the three minutes, the microwave shuts off… No burnt onions.

    Now I just need a reason to carmelize some onions… Maybe it’s time to for some French Onion Dip… Or Grilled Ham and Brie with Carmelized Onions.

  19. 33

    My method is super simple, much better than the microwave – I use three or four onion, butter, and a little salt, and throw it all in my crock pot for eight hours or so on low, depending on how brown and caramelised I prefer my onions; it’s a great way to make them in bulk for recipes through the week!

    • 34

      “Your” method is better? Why? You don’t even specify how much butter or how much salt (“a little”). Plus your method takes 8 hours. EIGHT. Maybe you should actually try AB’s method before making comments like that. Just like many of the previous commenters….TRY IT before you’re so quick to nay-say the recipe. Sheesh.

      • 35
        Will Jordan

        Her method is better, assuming it works, because she just has to dump everything in the slow cooker and then she walks away. The strength of the method is not the total time it takes to make the onions, but rather the total time the cook has to spend minding the onions. sheesh to you to.

  20. 41

    They don’t look very appealing at all. I think just putting them into a pan and caramelizing them the old fashioned way will yield a much better product. Not to mention – it’s easier and just as fast.

  21. 44
    Benjamin Hodgson

    What sort of wattage is your microwave? I love your recipes dearly, but I have a mistrust of any microwave recipe which doesn’t specify how I should use it.

  22. 45

    It seems like more work than its worth with this method. It’s easier for me to have a pan of onions on the stove while I’m busy cooking other things than to be microwaving something for 45 minutes… Nice try though!

  23. 48
    Larry F.

    Caramelizing onions is a major pain in the potato, but the results are so delicious. I can’t wait to try this method – thank you, Mr. B!

+ Leave a Comment