How to Caramelize Onions
Fact: Not many toppings compare to homemade carmelized onions.
Caramelized onions can add a sweet and savory spin to any sandwich, salad, or pizza, but their deep flavor doesn't come easy. It takes time and a little technique to gently coax that rich sweet flavor from the onions. Use your eyes, nose, and the photos below to guide you through the process of making perfectly caramelized onions.
Slice Your Onions
Begin by slicing four to six yellow onions. The onions will reduce in volume quite a bit as they caramelize, so it's important to caramelize multiple onions at once. Depending on the size, each onion will provide one to two servings once caramelized. Want to learn how to chop onions like a pro? Check out this video >>
Melt Butter & Oil
While onions can be caramelized in either butter or oil alone, using a combination of the two provides both flavor and a higher smoke point. Use approximately 1/2 tablespoon of butter or oil per onion (I'm using 1 tablespoon of butter and 1 tablespoon of oil for four onions). Using the widest skillet available, melt the butter and oil together over medium-low heat.
Once the butter is melted, add the onions and toss them in the butter and oil to coat. Sauté the onions slowly over medium-low heat, stirring occasionally.
Let Your Onions Sweat
After 15 minutes, the onions should be wilted and translucent. Aim to keep the heat low enough to allow the onions to sweat out their moisture without browning the edges. Continue to let the onions cook over medium-low heat, moving the onions around the skillet every few minutes.
Tan Your Onions
After 30 minutes, the onions will develop a dark blonde color. As the moisture in the skillet begins to evaporate away, the natural sugars in the onions will begin to caramelize develop the brown color. To ensure even caramelizing without burning the sugars, it's important to take it slow. Continue to stir and cook over medium-low heat.
Find the Fond
After 45 minutes, the onions will begin to brown. Most of the moisture should be gone from the skillet at this point, which may cause the sugars to coat to the bottom in a sticky brown film. This film is called "fond" and is packed full of that rich caramel flavor.
Stir, Scrape & Deglaze
To prevent the fond from burning on the bottom of the skillet, reduce the heat slightly and stir the onions a bit more frequently. To transfer that flavor off the bottom of the skillet and onto the onions, add a couple tablespoons of warm water to the skillet. Stir and scrape the fond to help it dissolve into the liquid. As the water evaporates, the delicious flavor will be deposited back onto the onions. You may need to repeat this deglazing process a couple times before the onions are fully caramelized.
The degree of caramelization is largely based on personal preference, but to achieve the deep brown, jam-like consistency shown above, the onions will require about one hour of cooking over low to medium-low heat. Because the process is long and requires a bit of work, it's always a good idea to cook more onions than needed. Leftover caramelized onions can be frozen, saving you time and effort later!
Want more? Watch this video for more onion caramelizing tips and tricks.