Follow this easy method for how to caramelize onions and you'll get a simple and sweet ingredient, side dish, condiment, appetizer - you name it - that pairs well with anything from a grilled burger to seared chicken to French onion soup.
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Caramelized onions are absolutely amazing and so easy to make yourself at home! The caramelization process of slowly cooking sweet onions over medium heat helps draw out the natural sugars and sweet flavor of the onions so they are super mild and absolutely delicious.
Pile your caramelized onions on top of burgers, sandwiches, steaks, chicken, pork chops, salads and more or stir them into soups, casseroles, dips, and other dishes for incredible flavor. The possibilities are pretty endless.
Caramelized onions get their name from the coloration and sweetness that happens during the cooking process. Cooking a raw onion until it is tender and caramelized not only changes the color but also cooks the natural sugars in the onion to give it a much sweeter flavor. While you may not want to bite into a raw onion like an apple, you may find that once caramelized, you can’t get enough of them.
They’re so good that you will want to make a big batch and store any extras in the fridge or freezer to have on hand!
What You'll Need
- Onions - You can really use any type of onion for this caramelized onion recipe, but white onions, vidalia onions, and yellow onions are our favorites. Red onions lose their color, so we tend to avoid those.
- Butter - A little salted butter adds a rich flavor that balances out the sweetness off the onions.
- Olive oil - This helps increase the smoke point of the butter and prevents the onions from sticking to the pan. Avocado oil is another good choice.
How to Caramelize Onions
- Slice off the top of the onion with a sharp knife on a cutting board, then cut the onion in half through the root end. Peel off the papery outer skin and discard. Slice the rest of the onion into thin slices about ¼" wide. You don't want them too narrow or they will burn more easily, but if they are too wide there won't be as much exposed surface area to caramelize.
- Heat the butter and oil in a large nonstick pan or cast iron skillet over medium-high heat until the butter has melted. Add in the onion slices and then stir to coat. Reduce the heat to medium to medium-low.
- Let the onions cook, stirring occasionally while the onions slowly caramelize. After 10 minutes, season the onions with a pinch of salt. The onions will release liquid and gradually brown as they cook. Be sure to occasionally stir them with a wooden spoon to prevent them from burning on the bottom.
- If the onions start to stick to the pan, add in a splash of water as needed and stir to scrape up any browned bits from the bottom of the pan and keep the onions from burning. You may need to repeat this one or two times with a little water so the onions don't dry out before they have had a chance to fully caramelize.
- The onions should be caramelized to a nice, deep golden brown color by around 30 minutes, although if you are using low heat it might take as long as 45 minutes. Just be sure to keep an eye on them so they don't dry out.
It takes a little patience to make caramelized onions as opposed to sauteed onions. For best results, you want to give the onions plenty of time to caramelize at a lower temperature, but if you want to speed up the cooking time you can either stop early before the onions are fully caramelized when they aren't quite such a deep brown color or increase the heat to medium-high to cook them a little faster. They are still delicious but won't have quite the same amount of depth of flavor as the slow cooked version.
You want your sweet caramelized onions to be a nice rich and deep brown color. Much more so than a simple golden shade. The longer your onions cook, the darker the shade of brown will be.
Yellow onions are simply the best for caramelizing because of the high sugar content. It’s also easily available where produce is sold and very versatile for many different dishes. Red onions turn to a fun deep purple color when caramelized and taste great as well. You want an onion with high sugar content so that you can get the good color and flavor you’re seeking, so sweet Vidalia onions are always a good choice.
Tips for Success
- It takes a little time to make the best caramelized onions, but it's worth it for the flavor they add to any dish.
- Keep in mind that the onions will cook down A LOT, so while the amount of onions might fill your skillet at first, you will end up with a much more reasonable looking amount of caramelized onions at the end of the whole process.
- If you want to tweak the flavor profile slightly, try adding a tablespoon of brown sugar or 1-2 tablespoons of balsamic vinegar to sweeten the onions even more.
Caramelized onions can be kept in an airtight container on the counter at room temperature for a few hours, but any longer than that and I would recommend refrigerating them for best results. They will keep in the fridge for up to 1 week.
Can I Freeze Caramelized Onions?
Absolutely! Caramelized onions freeze very well making them perfect for adding to a quick meal to get a deep and rich flavor without all of the added work. I recommend freezing them in different portion sizes like a muffin tin, ice cube trays, or small freezer bags so that it’s easier to grab the amount that you want when you want to use it.
More Onion Filled Recipes You'll Love
- Soy Glazed Mushroom Swiss Burgers
- All American Hamburger with Crispy Onion Strings and Burger Sauce
- One Pot Irish Potato Sausage Onion Stew
- One Pan Roasted Peppers Onions and Sausages
- Instant Pot French Onion Soup
Side Dish Recipes to Try
- Instant Pot Refried Beans
- Moist Cottage Cheese Cornbread
- Soft Garlic Parmesan Breadsticks
- Juicy Idaho Finger Steaks
- Bacon Wrapped Jalapeno Poppers
How to Make Caramelized Onions
- 1 Tablespoon salted butter
- 1 teaspoon olive oil
- 2-3 sweet yellow onions, sliced about ¼" thick
- Pinch of salt
- Cut off the tip of the onions, then slice them in half through the root end and peel off the papery outer skin. Use a sharp knife to slice them into thin strips.
- Melt butter and oil in a large pan or cast iron skillet over medium-high heat. Add onions and stir with a wooden spoon to coat. Reduce heat to medium to medium-low.
- Let the onions cook, stirring occasionally while the onions slowly caramelize. After 10 minutes, season the onions with a little salt. The onions will soften and release liquid as they gradually brown.
- If the onions start to stick to the pan, add a tablespoon or two of water and stir to keep the onions from burning.
- The onions should be caramelized to a nice, deep brown between 30-45 minutes.
- Storage: Caramelized onions can be kept in an airtight container on the counter at room temperature for a few hours, but any longer than that and I would recommend refrigerating them for best results. They will keep in the fridge for up to 1 week.
- Freezing: Freeze any unused onions in individual serving size containers or ice cube trays for up to 2 months. They can be added to soups or thawed and warmed in the microwave before enjoying.