I often see recipes that instruct you to sauté onions until caramelized, and suggest that this process will take 5-10 minutes. I’ve probably been guilty of this myself. Sure, you can brown some onions in 5-10 minutes, but they’ll be “stir fry onions” and missing the sweetness and depth of flavor of truly caramelized onions. That’s because the caramelization process takes up to an hour. It’s not you; it’s them.
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If you want to make the golden brown onions that fall off your fork and melt in your mouth, buckle up, grab a glass of wine, and set aside an hour or so to tend to your onions.
Tips for perfectly caramelized onions
Let’s start by defining “caramelized”. Onions have a natural sweetness and by cooking them low and slow, you can bring out that sweetness along with intense flavor and tenderness. They’re amazing on pizza, sandwiches, and essential for dishes like French onion soup.
The most important factor in caramelizing onions is time, and there are a few other variables that affect how long it take to make them,
Don’t overcrowd the pan
It already takes a long time to caramelize onions—don’t prolong the process by using a pan that’s too small for the amount of onions you’re cooking. Onions let out their moisture, or “sweat”, as they cook, and it will be tough to make them start browning if there’s too much moisture in the pan. And no, using a bigger pan won’t make the onions caramelize faster.
Take your time
Don’t be tempted to turn up the heat to caramelize your onions. Your onions will brown, but not in the right way. They’ll have a little char, which is nice in a quick stir fry, but they won’t be caramelized.
Use oil or full-fat vegan butter or margarine
Avoid using low-fat or “whipped” vegan margarine because the moisture content will be far too high. We want to brown the onions, not boil them.
Slice your onions evenly
Even is the name of the game. Your onions will cook evenly if all of the slices are the same size. Also make sure to separate the rings of onion from the slices.
Use the right amount of heat
A low-medium flame is the right amount of heat for your onions. Turning the heat up too high is a common mistake, but so is keeping it too low. If your onions are still white after 20 minutes, bump up the heat a bit. Worst case scenario, they take a little longer to cook.
Add some fresh herbs
If you’d like to infuse your onions with more flavor, toss a sprig of fresh thyme or rosemary in the pan partway through the process. Totally optional, but delicious.
The stages of caramelizing onions
If you’d like an idea of what your onions will look like at each stage of cooking, use the photos below for reference. Keep in mind I made a big batch of onions (I probably could have used fewer onions), so yours will cook faster if you’re cooking a smaller amount of onions.
The onions are just starting to soften, let out their moisture, and have not started to turn golden in any way.
The onions are soft and just starting to change color. They’re no longer firm at this point, especially if you’ve been stirring them so they soften evenly.
We’re seeing some golden hues at this point and they’re totally delicious at this point on pasta or a burger, but they’re not yet caramelized.
The volume of onions has shrunken significantly at this point because they’ve let out so much moisture, and we’re getting some caramelization started at this stage.
These onions are lightly caramelized (with some medium caramelization in there—I know, I know, it’s not even). You can stop here, or keep going.
Here we are at the hour mark with a big pot of onions. This is a nice level of light-medium caramelization and a few shades darker than 10 minutes earlier. You could keep going until they’re a dark brown, and that change will happen faster than it took to get through the earlier stages.
Shortcuts for caramelized onions
There are a few shortcuts you can use to speed up the caramelization process if you’d like. I wouldn’t necessarily recommend using a shortcut because the amount of time it saves is negligible, and caramelizing onions isn’t something that you usually do when you’re making a quick weeknight dinner.
The baking soda method
Adding a pinch of baking soda to your onions at the beginning can help speed up the reaction that caramelizes the onions.
The slow cooker method
As we talked about above, part of getting an evenly caramelized onion is stirring them throughout the process. A slow cooker will caramelize the onions, but the onions in the center of the slow cooker won’t get much love like the ones directly on the sides of the slow cooker. A way around this would be to stir the onions a few times throughout the slow cooker process.
- 3-4 tablespoons olive oil or full-fat vegan butter see note
- 4 onions sliced
- 1 teaspoon salt
- Heat the oil or vegan butter in a large pot or cast iron pan over low-medium heat.
- Add the onions and sauté, stirring occasionally.
- After 15-20 minutes, add the salt and continue cooking.
- Continue cooking the onions until they reach desired level of caramelized, 45-60 minutes total.
- If you use vegan butter or margarine, avoid using reduced fat or "whipped" varieties. These kinds will have a higher water content, so it will take a very long time for the onions to start turning golden.
- Make sure you use a large enough pot or pan for the amount of onions you're using. It will take a long time if your pan is crowded.
- The time it takes for your onions to caramelize will vary depending on the amount of onions you use, the water content of the onions, the size of the pan, the level of heat, and the type of oil or margarine you use. Just be patient, and avoid turning up the heat on the stove too high.
How to use your caramelized onions
Put them on a sandwich or sausage
Caramelized onions are great mixed with green peppers on a burger, sandwich, or sausage (like a vegan brat or Italian sausage).
Add them to pizza
I see your sliced onions and raise you caramelized onions on pizza. Or use both because each one brings a totally different flavor to the party. Try them on my Cheeseburger Pizza or Buffalo Cauliflower Pizza.
Add them to hummus or other dips
You can blend these onions into hummus, or top your hummus with the onions (and maybe some roasted garlic), a drizzle of olive oil, and a sprinkle of salt and sumac. Uh-mazing!
Use them in French onion soup
That’s exactly what I used these onions for…stay tuned for the recipe!