Caramelized onions are good on pretty much…everything. The only problem? They're surprisingly tricky to make. They take time to slowly brown and caramelize. It's easy to burn them—and it's easy to remove them from the stove before they're actually done. So we talked to senior associate food editor Claire Saffitz in the test kitchen to figure out the common mistakes people make when they try to make this deeply flavored accoutrement.
1. Slicing Them Too Thinly
Thinly sliced onions will burn faster and stick to the bottom of your pan. Aim to slice your onions 1/8" thick—their heft will prevent them from drying out.
2. Using Just Butter
You definitely want the flavor of butter in your onions—but butter has the tendency to burn. For insurance, use a combination of butter and oil, which has a higher smoking point. But how much do you use? Depending on the consistency you want your onions, you can use more or less fat. Just cover the bottom of your pan for jammy, soft caramelized onions, or add a little more for more structured, slightly charred caramelized onions. The more fat in the pan, the more the onions will fry rather than soften. (Okay, you can fry them a little.) You can use just oil, or a combination of butter and oil—the choice is yours!
Brown food never looked so good. Photo: Danny Kim
3. Crowding the Pan
If you pack too many onions into your pan, they'll steam and produce water. Eventually, they will caramelize—but it will take much longer to get them there. In a 12" pan, you'll ideally be able to cook 2 large onions (we like yellow or Spanish onions) without encountering any steaming problems.
4. Cranking the Heat
You're not sautéing your onions—you're trying to slowly coax flavor out of them. It takes time, probably a solid 45 minutes, for the onions' sugars to caramelize. If your heat is too high, the onions will burn. Heat your pan over medium-low, then add your onions. Keep it on that temp for the whole process. No cheating!
5. Skipping the Deglazing Step
As our boss's tweet reminded us, there's flavor in the bottom of the pan, too. Take full advantage of the brown bits and deglaze with stock, wine, beer, vinegar, or even water—whichever liquid matches the dish you're going to be adding your onions to. Stir to incorporate with the onions, and they'll absorb all that flavorful liquid, making them EVEN BETTER.
