What Are Caramelized Onions?
Caramelization transforms onions by adding fat, liquids, and heat to remove moisture without burning. The flavor and sugar remain as the onions simmer and water boils out. As the onions continue to cook, the color of the onions darkens to a golden hue from the sugar caramelizing. This creates an onion that is sweeter and packed with flavor. Caramelized onions are a popular addition to pizzas, burgers, salads, and even omelets! Any recipe that adds plain onions can substitute with caramelized onions. Best of all, you can easily make this recipe at home.
What Types of Fat to Use
When making caramelized onions at home, there are a lot of variations you can use to create a custom flavor. Ingredients will vary from kitchen to kitchen, including the fat used. Some cooks prefer to use butter as a fat, while others choose olive oil. If you like, you can also add coconut or vegetable oil. I’ve found that olive oil or butter produces the best results. The flavors aren’t too intense and absorb well into the onions. When adding fats, a little goes a long way. You only need a tablespoon or two of fat for every 3 to 4 medium-sized onions. It provides enough oil to crisp the onions and prevents sticking without burning them.
Liquids Add Flavor to Caramelized Onions
It may seem counterintuitive to add liquids that cook away, but it’s an important addition. Incorporating liquids provides an environment for the sugar to caramelize without burning the onions. If using a flavored liquid, the flavors remain and enhance the onions. For a milder flavor, you can use water. Try using balsamic vinegar, red wine vinegar, or even whisky to create layers of flavor! It all depends on what flavors you are pairing with the onions. Balsamic vinegar is a safe bet for complimenting multiple dishes.
Brown Sugar Enhances the Caramelization
Adding a little bit of salt and light brown sugar can enhance the caramelization process of onions. Salt helps to absorb moisture from onions to speed up the process. While onions have enough sugar to caramelize, adding brown sugar can create richer golden colors and add some flavor from the molasses. While salt and sugar are optional, I always add them when making caramelized onions.
How Long to Caramelize Onions?
There are a few factors that will influence the caramelizing time of onions. The two most influential factors are the number of onions cut and the pan’s temperature. A larger quantity of onion and thicker slices will require more time for the moisture to cook off. Higher heat will also affect how quickly the liquid absorbs and the sugar caramelizes. The recipe in this article uses three to four medium onions, and the cooking time can range from 30 minutes to an hour. Thinner slices, lower amounts of moisture, and higher heat will shorten the cooking time. It will, however, increase the risk of uneven caramelizing.
- 4 yellow onions medium, thinly sliced
- 2 tbsp olive oil
- 1/4 cup balsamic vinegar
- 2 tbsp light brown sugar
- 1 tsp salt
- Peel and cut the onions in half, cutting from stem to stem. Thinly slice the onion halves into strips, cutting from stem to stem again. Set aside.
- Heat a pan over medium-low heat on a stovetop
- Add the olive oil and onion slices, stirring to coat
- After five minutes, add the balsamic vinegar, brown sugar, and salt, stirring to coat
- Continue to cook the onions over medium low heat, stirring the onions every five minutes.
- If the edges begin to brown too quickly, lower the heat slightly. You can also add a small amount of water to slow the cooking process.
- Once the onions have turned a dark golden-brown color, remove from heat
- Serve immediately
I love caramelized onions because of how customizable the recipe can be, from the quantity made to the ingredients used. For every two medium onions, a general guide uses a tablespoon of fat and two tablespoons of liquid. A tablespoon for every two onions is a good amount if adding brown sugar. If you haven’t made caramelized onions prior, I suggest doubling the amount you think you may need. The onions will cook down quite a bit, sometimes to a quarter of the amount added to a pan. Keep that in mind when purchasing onions. If you have leftover onions, they can be refrigerated in an air-tight container for up to seven days.