Like a lot of cooking skills that seem basic, making caramelized onions is actually more complicated than it appears. When I first started trying to make them, all of my attempts were total flops. I'd heard they were the kind of thing you could just set and forget, but when I did that, I'd always come back to find my onions nothing like I expected—somehow undercooked and overcooked all at the same time.
As is often the case, my problem was that I was being impatient. What I didn't realize at the time is that caramelizing onions is less about setting and forgetting and more about going low and slow. If you rush through the process and crank up the heat, your onions are more likely to burn than caramelize. But if you take your time, you'll find that they're actually pretty easy to cook and surprisingly forgiving if you make a mistake.
Plus, it's definitely worth learning how to make caramelized onions because there so many delicious ways to use them in your food—they're basically the candy of the vegetable world. With this guide that I've created using both expert advice and my own experience, you'll finally learn how to caramelize onions perfectly, too.
Use more onions than you think you need, because they will shrink down.
Since caramelized onions take a while to cook, it's best to make a large batch at once. Not only that, but onions shrink a lot during the cooking process—one small onion will yield about a tablespoon or two of caramelized onions—so it's really not even worth it unless you're cooking a bunch. At minimum, I'd suggest using about eight onions every time. Your pan will be brimming and it should look like this:
Cut the onions into long, 1/4-inch-thick strips for best results.
These are also known as julienne slices. This is the best size to cut the onions for a final product that's tender and jammy like caramelized onions should be, but not complete mush, says Christine Hazel, recent winner of Food Network's Chopped. If you cut them thicker than that, they'll need longer on the stovetop and may cook unevenly, and if you cut them thinner they'll turn into mush, she explains. It's OK if they're not perfectly even, but in general, a 1/4-inch cut is what you should aim for.
Luckily, cutting them like this is easy, because all you need to do is slice on the lines that naturally appear on the onion. To do it, start by peeling the onion and cutting off the ends, Nicolas Caicedo, executive chef of The Williamsburg Hotel, tells SELF. Then, slice it in half and set it with the recently-sliced side down. When you look at the halved onion, you'll notice a series of lines running across the top. Use them as a guideline for chopping, and your slices will be the perfect size.
Salt the onions right before you start cooking to help draw out moisture.
Unlike mushrooms, which shouldn't be salted until after they've browned, you should always salt onions before you start cooking them. Onions won't begin to caramelize until all the water in them has evaporated, and using salt will speed up that process, Caicedo explains.
Cook them in a fat source over a medium-low heat for about 45 minutes to an hour. Check on them about every 10 minutes.
Caicedo says that you'll always need to cook the onion in a fat source, but that it can be just about whatever you want. "I recommend using the fat source that works best in your dish," he says. Personally, I like to use a combo of butter and olive oil—about a tablespoon of each for eight onions—but you could easily use one or the other if you prefer. Just be sure that your onions are thoroughly coated in whichever one you choose. If a tablespoon or two isn't enough to accomplish that, don't be afraid to add more.
Start the onions at a medium heat and let them cook until much of their moisture has steamed off—about 10 minutes. You don't need to stir the onions at this point, just let them do their thing. Then, bring the heat down to medium-low, give the onions a stir, and come back to check on them in another 10 minutes. In general, try to stir them as little as possible because consistent contact with direct heat is what will help produce a perfectly caramelized final product.
If you notice brown bits forming, a bit of water will save the day.
If you come back and notice that your onions are starting to get a little black and brown in some places, don't freak out. Caicedo says that all you need to do is add a bit of water, which will deglaze the brown bits and add color and flavor to the onions. No matter how far from repair they may seem, you can probably fix them with a splash of water or two. As long as you keep the heat low, there's really no way to mess them up at this point.
You'll know the onions are ready when they're deep brown in color and jammy in texture.
They should also be fully translucent and completely sweet. If they're still kind of crunchy, or they still have some of that raw onion bite, let them cook for a bit longer.
Refrigerate them in a tightly sealed container and enjoy for about a week.
Hazel says that your caramelized onions will be good to eat for five to seven days, so they're a great addition to your Sunday meal prep plans. Make a huge batch while you're working on everything else, check on it occasionally, and you'll be able to enjoy caramelized onions with every meal before you know it. And they really work well in just about anything—try them in pasta and salads, on burgers and sandwiches, or in soups and casseroles. There's no way to go wrong.