How to Caramelize Onions
Yes, there’s some technique involved. But we break it down into steps and arm you with a number of smart tips.
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By Layla Khoury-Hanold for Food Network Kitchen
Layla Khoury-Hanold is a contributor at Food Network.
Onions are an everyday, flavor foundation-building ingredient that need just a little heat and time to transform their taste from sharp to mellow. But when you take the extra time to caramelize them, the humble onion is transformed into a sweet, flavor-enhancing powerhouse. Caramelized onions take a starring turn in dishes such as French onion soup, but they play an excellent supporting role in all manner of dishes: to top burgers or enhance grilled cheese sandwiches, mixed into scrambled eggs or frittatas, folded into dips, piled onto pizza and salad or simply scattered over noodles, rice or potatoes.
Best Onions for Caramelizing
You can caramelize any kind of onion, but yellow or Spanish onions tend to offer the most balanced-sweet-savory flavor profile and are the most versatile for different dishes. Sweet onions, such as Vidalia or Walla Walla work too, but keep in mind that their flavor will become even sweeter once caramelized. Red onions are typically better suited for quick-cooking techniques, such as grilling or broiling. You can caramelize red onions, but they tend to take on much more color than their yellow or sweet counterparts. White onions can be used but tend to produce a one-note sweet flavor that lacks the savory depth of yellow caramelized onions.
How Long Does It Take to Caramelize Onions?
It depends on how many onions you’re caramelizing at once, but plan on the process taking 45 minutes to an hour. Since it’s a lengthy recipe, it can be advantageous to cook a big batch, say 4 to 5 onions, at once. You can reduce the required cook time by caramelizing 1 or 2 onions at a time. The amount of time also depends on how old the onions are as well as their water and sugar content.
What Does Caramelized Color Look Like?
There are three different stages of caramelized onions, each with their own signature color. Blonde caramelized onions are done after about 15 to 20 minutes; they retain a bit of bite and are ideal for French onion soup. Cook the onions another 15 to 20 minutes for golden brown caramelized onions that are softer and more caramelized. These traditional caramelized onions are excellent in quiches and grilled cheese sandwiches. For dark brown caramelized onions with slightly crisp edges, cook onions for another 10 to 15 minutes, watching carefully to avoid burning. Deeply caramelized onions make an excellent topping for burgers and steaks.
A Step-by-Step Guide to Caramelizing Onions
Caramelized onions can be tricky, but master this basic Caramelized Onions recipe and you’ll be on your way to consistently golden and jammy onions in no time.
2 tablespoons unsalted butter (or olive oil or avocado oil, or a mix of butter and oil)
2 large yellow onions peeled and thinly sliced
1/4 cup water (or broth), plus more for deglazing as you cook
Use a heavy-bottomed pot or pan with high sides, such as one made from stainless steel or cast iron. This ensures even heat distribution and prevents hot and cold spots that could result in uneven cooking results. You can use a non-stick skillet, but the key to deeply flavorful caramelized onions lies in the formation of a fond, the browned bits of onion that stick to the bottom of the pan, which aren’t easy to achieve when using a non-stick pan. Be sure to choose a large pan, as the onions need plenty of room to cook; if they’re too crowded, they’ll steam instead of brown.
You’ll also need a wooden spoon for stirring the onions and scraping the pan.
1: Add Oil to the Pan
Heat 2 Tablespoons of unsalted butter (or a mix of butter and oil) in a large pan over medium heat.
2: Add Onions In Batches
Add enough to form a single layer to the pan, add a pinch of salt, and toss to coat with butter/fat mixture. Cook onions and stir until onions turn translucent, 1 to 2 minutes. Add another layer of onions and pinch of salt, tossing to coat, stirring to cook for 1 to 2 minutes. Repeat the process until you’ve added all the onions.
3: Cook Over Medium Low, Stirring Occasionally
Reduce the heat to medium-low, continue cooking, stirring occasionally to let the onions brown, about 15 to 20 minutes. At this point, you’ll have blonde caramelized onions. For a jammier consistency, continue cooking the onions, stirring occasionally until they are well-browned, about 15 to 20 minutes. If they start to stick and burn, stir in a little water to loosen them and use a wooden spoon to dislodge them. For dark-golden brown onions with crisp edges, cook another 10 to 15 minutes, paying close attention so they don’t burn.
4: Deglaze the Pan
Once you’ve finished cooking the onions to desired doneness, deglaze the pan with 1/4 cup of water (for extra flavor, you can also use vegetable or chicken broth, balsamic vinegar, red, white or Madeira wine, beer or brandy).
5: Serve or Store
Serve warm, or let cool, then store in an airtight container in the refrigerator for up to one week or in the freezer for up to three months.
How to Caramelize Onions Fast
The hardest part about making caramelized onions is the patience required. But time is necessary for the onions to release their water and proteins and allow flavors to concentrate. It can be tempting to bump up the heat, but you’ll risk scorching the onions. While there’s no substitute for caramelizing onions low and slow to get that complex savory flavor, there are a few shortcuts to speed things along if you’re in a rush.
- Add sugar: some cooks swear by adding a pinch of sugar to enhance the onions’ sugar content and help them caramelize faster.
- Add baking soda: dissolve a 1/8 teaspoon baking soda in 1 tablespoon of water and add the mixture to the onions toward the end of cooking (about 15 to 20 minutes in). Stir continuously for about 30 seconds, or until the mixture has evaporated.
- Deglaze as you go: when the sticky bits of onion (called the fond) start sticking to the bottom of the pan, add a few tablespoons of water to loosen them, then scrape them up with a wooden spoon. The browned bits will dissolve in the water and disperse amongst the onions, yielding dark, sweet onions. Adding water to the pan as you go also helps keep the onions from drying out.
Can You Freeze Caramelized Onions?
Caramelized onions freeze beautifully, all the more reason to make a big batch while you’re taking the time. Once the caramelized onions have cooled, scoop tablespoon-fulls onto a parchment paper-lined baking sheet, freeze for an hour, then transfer the frozen portions to a resealable freezer-safe bag or air-tight container. Or make portions by filling an ice cube tray and freezing, then transfer to a freezer-safe bag or container. This way, you can thaw just what you need, whether it’s a bag-full for a jammy onion pasta sauce or just a dollop for a sandwich topping. Caramelized onions will keep for up to 3 months in the freezer.
Caramelized Onion Recipes
Sweet-savory caramelized onions bolster beef stock to form the base of this classic bistro dish, all capped off with toasty slices of baguette and melty Gruyere. Pro tip: Slice the onions from stem to root. This allows them to retain more of their shape during cooking than when sliced crosswise.
This rich brunch dish gets bursts of flavor from sausage, sourdough, Parmesan and Muenster. But what really takes it over the top is the addition of caramelized onions, which get a deeply savory note from being cooked low and slow in the rendered breakfast sausage fat.
Cooking onions and mushrooms together low-and-slow creates a dynamic duo of umami goodness in this tasty vegetarian dish. The deeply browned mushrooms and caramelized onions impart loads of flavor with less oil, and make a perfect counterpart to nutty, chewy whole wheat noodles.
Caramelized onions anchor this game-day ready dip, with a sweet-savory punch that offers the perfect foil to tangy sour cream, creamy mayonnaise and Worcestershire. This make-ahead dip comes together in under 30 minutes of hands-on cook time; the hardest part is waiting for the dip to chill in the fridge, but the longer it sits, the more the flavors mingle.
Stirring savory-sweet caramelized onions into mashed potatoes elevates an everyday, go-to side dish to special occasion status. Bookmark this one for your Thanksgiving feast, and be prepared to share the recipe.
For a more hands-off approach, employ your Instant Pot. After melting the butter in the pot and sauteing the onions for a couple minutes, you’ll pressure cook for just 4 minutes to achieve blonde caramelized onions. If you want saucier, more deeply golden onions, you can continue cooking and stirring the onions in the pot after the pressure cook cycle completes, about 30 minutes.