June 7, 2009

Pantry: Caramelized Onions

Caramelized Onions
Caramelized Onions

When sweet onions are on special I set aside half a day to make caramelized onions because they add an incredible amount of flavor to any dish. Most recipes call for several minutes of cooking. I take at least four hours.

Sliced onions ready to caramelize
Start by slicing the onions. Unless the onions are small, I'll quarter them first to avoid long strands in the finished product. Then add to a pan with about 4 tablespoons of unsalted butter. A neutral extra virgin olive oil works just as well if you want to avoid that small amount of dairy.

The heat is medium-low. Listen for cooking sounds. If you hear anything above just a whisper, the heat is too high. Stir every quarter hour or so.

Onions after an hour
After an hour, the onions are happily giving up all their water, and the volume is beginning to reduce. If you've used regular yellow onions, you might want to add a teaspoon or two of sugar at this point. During the second hour of cooking, the volume will reduce to about a quarter of the original amount.

Onions after three hours
Three hours into cooking the pan is mostly dry and the first signs of color appear. At this point you'll need to start paying much closer attention. If there are any hot spots in your pan or heat source, you'll see spots of color in the onions. Just be sure to stir more frequently and everything will be fine.

Onions after four hours
After four hours you'll have nice color development and lots of sweetness. If you must, add a pinch of fleur de sel at this point, but I never do. Don't walk away from the pan because the onions can burn even at the low temperature you're using. Continue stirring until the onions have darkened as much as you want, or until your patience runs out.

That's it. Refrigerate and use in anything that calls for onions. If you feel ambitious, proceed on to make some Sweet Onion Marmalade. Once you've tried caramelizing your onions this slowly, you'll never go back to high heat.


  1. Really interesting, I'll have to try this out. How do these keep in the fridge for? And can you freeze them afterwards or would they start to lose their flavor doing so?

  2. Thanks!. They'll keep for 7-10 days in the refrigerator. I don't know about freezing, I think they wouldn't hold up well. I've never been able to keep them around for more than a few days because I use them in almost everything when they're around.

  3. "Patience is a virtue", I'm starting to find out that I only posses it sometimes. I never let onions cook for more than 1 hour when I caramelized them.
    Do you use vidalia onions?

  4. The flavor difference between 1 hour and 4 hours is significant because flavor takes time. Vidalias are excellent sweet onions, and they happen to be the type used in this post.

  5. We make caramelized onions ALOT and eat them on and with just about everything. We found that on the rare occasion we make more than we can eat, you can freeze them in a zip lock bag and then break off as much as you need when you want some to top a pizza or throw in some soup or whatever.

  6. Great! There it is, from someone who's tried. Go ahead and freeze 'em, if any happen to be left over.