Caramelized onions are one of my favorite things and it hurts my heart when I see a recipe that includes caramelized onions and the instructions are basically, “cook on medium-high heat for 10 minutes, until caramelized.”
No! Stop it! That is not how you caramelize onions!
Even at a restaurant, I’ll often order something with caramelized onions, and the onions are still white and even a little bit crisp. I generally consider myself a pretty chill person—I wasn’t always, but wisdom and age will do that to you—but this drives me nuts.
Onions caramelize when you cook them low and slow. How slow? Well, it’s taken me anywhere from 45 minutes to 2 hours. Of course, the time also depends on how dark you want your onions–a deep brown will take you longer than more of a golden color.
So here’s how to caramelize onions for real. I’m not a chef, nor do I play one on TV, but I am a person who takes caramelized onions super seriously. I think that makes me an authority, right?
I usually start with two large onions—when you caramelize onions, you don’t want your skillet too crowded or too empty, so this is usually the perfect amount. Slice them up nice and thin.
If you’re unconcerned about calories, heat a large skillet on medium-low (or just a notch below that–my stovetop tends to cook a little hot, so I keep it just under medium-low) and pour in some olive oil or add a few pats of butter. Go wild! But if you’re not the wild type, two tablespoons of either is just fine.
Now, you stir in your onions and you wait…
At the beginning, things will go slow. I’ll stir every 5 minutes or so. It’s hard to see any progress and you’ll be tempted to turn up the heat. Don’t do it! Patience is a virtue that results in the most delicious caramelized onions.
Then, things start happening. The onions begin to cook down. They’re beginning to darken a bit. Now’s the time when you’ll want to start stirring more often and keeping a closer eye on things.
At some point, especially if you measured out your oil or butter, your pan will start to get dry, as will your onions. When this starts happening, add a splash of water, stock, or vinegar. Vinegar is nice if you plan on using your onions on a sandwich or burger, but otherwise, I’d stick with water or stock.
Stir in about a tablespoon, and once it evaporates, add another and keep repeating the process, scraping off any burnt off bits at the bottom of the pan. If you don’t add liquid, you’ll end up with dried out onions; what we want are onions that are almost jammy in texture.
Once the onions reach a nice, golden brown, you can take them off the heat and use ’em or store ’em, but you can keep going until they’re a darker brown. It’s up to you! Just note that as the onions start to darken, you’ll want to keep a close watch to make sure they don’t burn.
Notice I don’t have any times listed here? That’s because it seems to be different for me every time I make caramelized onions. And for this reason, I usually make my caramelized onions in advance and store them in the fridge or freezer for when I need them. They’ll keep in the fridge for about a week and in the freezer for up to 3 months.