How to caramelize onions

We usually think of onions as really pungent and something that should be eaten in limited amounts — if at all — because of their really strong nature. And, like garlic, your chances of getting a kiss after eating them decreases with each bite.

But it doesn’t have to be this way. Onions can actually transform into a soft, delicious ingredient that is almost as sweet as candy. We often call these “caramelized” onions, and all it takes to make them is a little heat and a lot of patience.

In a process that’s almost like making caramel, what we’re doing when we caramelize onions is break down their sugars via the heat. Not to get all geeky, but suffice to say that this process causes a chemical reaction in the onions starches (sugars) to make them really sweet and really tasty. Oh, and they turn a brown, caramel color.

(For those who really want to get their culinary nerdishness on, what is technically happening when we “caramelize” onions is known as the Maillard reaction — say “may-yard” — a type of browning that happens when starches are in the presence of proteins. For more on this kind of stuff, check out the book “What Einstein Told his Cook,” by chemist Robert L. Wolke and check out this campy video of these processes at work.)

OK, still with me after all that? No more science lessons, I promise. Let’s get back to those onions.

Now, that’s all good and fine that we can transform onions into something delicious, but what in the heck do we do with them after that? Admittedly, only the most devoted onion fan would eat them caramelized as is. Their real starring role comes into play when we use them in recipes such as French onion soup or on top of bread with cheese in what I call French Onion Bruschetta.

Without further adieu, here’s how to caramelize onions yourself.

Step 1: Grab a bunch of — you guessed it — onions, and peel and slice them. White, yellow or brown onions will work; red ones can be a little too pungent for what we’re doing. Four to five medium-size onions will be plenty enough.

Step 2: Now grab a heavy pot — enameled cast-iron works great if you have it — that is at least five quarts.

Step 3: After the onions are all sliced, melt some butter in the pot. How much butter? I’d say as much as you’d like, but that wouldn’t be very healthful. About a quarter stick will be plenty enough. Melt the butter over medium heat and swirl it around with a wooden or plastic utensil.

Step 4: Dump in the onions and mix them around so they coated with the butter. Cook them for 15 minutes, uncovered, stirring once in a while. I also like to put a little salt and pepper on them at this point. And don’t be afraid to try some herbs, as well, such as dried thyme. It’s really hard to mess this up because the onions are so strong.

Step 5: After 15 minutes, the onions will have started to brown, as seen above. What we’ll do now is put a lid on the pot, turn the heat to low, and just let the heat do its magic. Cook the onions for 30-40 minutes, taking off the lid once in a while to stir. The end product will look like the picture below, with dark brown onions surrounded by their sweet juices that have come out in the cooking process. It’s all edible and delicious.

Congrats, you’ve just made caramelized onions! Where to go from here? Well I suppose if you really love onions you could just eat them as is, but the real place for these things are in recipes such as French Onion Soup or one of my favorites: French Onion Bruschetta. Try making these yourself and share how you use them in the comments below.


  1. Krissi said,

    January 13, 2010 @ 3:23 pm

    This was SO delicious! And the fragrant smell that floats through the whole house is incredible!
    Thanks ‘I want to cook-guy’!


  2. Dennis said,

    March 12, 2010 @ 4:55 pm

    Great… thanks. Love them.

    A similar version can be used as garnish on a barbecue steak:

    Cut up 1 medium sized onion
    Using a skillet (non-stick works too) over medium heat add 2-3 tablespoon olive oil
    Add onion and stir occasionally until moderately caramelized

    Garnish steak with caramelized onion and enjoy
    Nice on bake & server pizza too. Just place caramelized onion on pizza before baking.

  3. I Want To Cook » How to make caramelized onions said,

    July 1, 2010 @ 5:07 am

    [...] Hello and I’m glad you found I Want To Cook! If you’re looking for the how-to on making caramelized onions that was featured in today’s Orange County Register newspaper, you’ll find it right HERE. [...]

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