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Home > All Recipes > French Vegetable Recipes

How To Make Caramelized Onions Perfectly

Published: Sep 3, 2021 · Modified: Nov 23, 2024 by Judith Coates · This post may contain affiliate links · Leave a Comment

Bon Appetit
Like it? ~ Let us know below!
There are many dishes that caramelized onions will transform into a most delicious experience when they are perfectly done.
Jump to Recipe Print Recipe Pin Recipe
Golden color onions with some having a brown edge.

Know Your Onion!

Caramelized onions, make a flavorful addition to many dishes and is one of nature's most ubiquitous vegetables, just add a little heat and it transforms them into a supple and sweet dish. Learn the technique for making perfect caramelized onions!

Golden color onions with some having a brown edge.

And, if you don't care about the details of the technique either, just skip the science lesson and go to the recipe. 😉

Jump to:
  • Know Your Onion!
  • What Is Caramelization?
  • When Will The Caramelized Onion Take Place?
  • What Recipes To Use These In
  • In Curries Too
  • More Recipes For This Technique
  • 📖 Recipe

What Is Caramelization?

In the simplest terms, caramelization is the browning process that occurs when sugar is heated.

However, there are numerous forms of caramelization depending on the types of sugars in the food and the kind of reaction taking place.

The specific kind of browning taking place when you heat an onion is called pyrolysis. This is a non-enzymatic form of browning, meaning it isn't taking place as a result of contact with oxygen, but rather a chemical process.

An easy way to picture the difference between non-enzymatic and enzymatic browning is to imagine the contrasting reactions that a sliced apple and sliced onion have to oxygen.

While a sliced apple will begin to turn brown soon after making contact with the oxygen (aka. enzymatic browning), the sliced onion will stay its same color even after prolonged exposure to air.

When Will The Caramelized Onion Take Place?

An onion can only be browned when it comes into contact with a heat source, which causes a reaction that not only changes the physical appearance of the onion, but also the chemical makeup. The key to this reaction is the natural sugars that are already contained within raw onions to transform them into delicious caramelised onions.

This chemical process occurs when the onion comes in contact with heat, causing the temperature within the cells of the onion to rise.

Once this temperature reaches a certain point, pyrolysis occurs, causing the larger starch and sugar molecules of the vegetable begin to break down into smaller units.

This happens when the heat causes the cellular bonds that link the large sugars together to break apart, transforming them into the single molecules that give the onion a sweeter, milder flavor.

Caramelizing an onion to perfection requires time and patience, as the onion - which is about 90 percent water to begin with - needs to sweat out a significant amount of that liquid. This release of water is key to the caramelization process because this excess liquid allows the onion's structure to begin to break down, and for the vegetable to start to soften.

During this process the texture and appearance of the vegetable is also altered, as the structural starches in the onion break down as well, seemingly magically transforming the onion from yellow or white, crunchy, and astringent to golden brown, soft, and subtly sweet.

What Recipes To Use These In

  • In French Onion Soup is a must!
  • Pissaladière is a delicious oniony tart that is deliciously similar to pizza that calls for caramelized onions.

In Curries Too

  • Easy Chicken Curry Recipe
  • Coconut Fish And Shrimp Curry Recipe
  • Easy Chicken And Chickpea Curry
  • Coconut Beef Curry
  • Beef Curry Recipe
  • Most Delectable Chicken And Vegetable Curry Recipe

More Recipes For This Technique

  • Classic French Onion Soup Recipe
  • Tomato Sauce Recipe
  • Onion Tart Recipe
  • Brown Sauce

📖 Recipe

Golden color onions with some having a brown edge.

How To Make Caramelized Onions Perfectly

Judith Coates
Bon Appetit
Like it? ~ Let us know below!
There are many dishes that caramelized onions will transform into a most delicious experience when they are perfectly done.
Print Recipe Pin
Prep Time 10 minutes mins
Cook Time 30 minutes mins
Total Time 40 minutes mins
Course vegetable
Cuisine French

Ingredients

  • Any amount of onion you will need for your purpose.
  • All onions will caramelize so pick your favorite.
  • 1 tablespoon butter or oil per pound of onion

Instructions
 

  • To prep for the caramelization process, start by slicing your onions into thin, even pieces. More even slices will make for more even caramelization overall.
  • Add a tablespoon of oil or butter per pound of onion to a skillet over medium heat until it has become hot, but not smoking.
  • Add your onions to the oil or butter, coating all of the pieces in the fat and spreading them out evenly over the entire pan to begin the 'sweating' process, which will take anywhere from 10-30 minutes depending on the quantity you're cooking.
  • Stir the onions occasionally, increasing the frequency of your stirring once the onions have begun to brown.
  • Despite the textural change that you'll see in your onions as a result of the sweating period, the actual pyrolysis reaction that causes caramelization doesn't occur until the internal temperature of the onions has reached 100°C.
  • So, if you become impatient and remove the onions from the pot as soon as they get soft, your onions will lack the deep flavor and color that results from pyrolysis.
  • At this point, it's imperative to keep a close eye on your vegetables to make sure they don't burn, stirring them every few minutes to prevent sticking to the pan or charring.
  • If your onions appear to be sticking to the pan, add a couple of tablespoons of water, wine, or stock to the vegetables.
  • Once your onions begin to caramelize, you can optionally turn the heat down slightly to prevent possible burning.
  • You also have the option to add in a pinch of sugar or even a tablespoon or two of balsamic vinegar, which allows them to develop an even sweeter, more caramelized flavor.
  • Overall, the process should take between 30-60 minutes to unleash the full depth of flavor from the onions.
  • You can then use the finished onions in many recipes, not just French onion soup; use them on pizzas, or serve just as a side dish, or use in pasta dishes to add a sumptuous flavor. They work perfectly well, too, in curries like the recipe list above.

Notes

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Keyword caramelized onions, French food, french onion soup, how to cook
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Bonjour

I’m Judith Coates,

creator & chef behind Love French Food. Whether you’re discovering French cuisine for the first time or refining your culinary skills, I’m here to guide you with authentic French recipes anyone can make, kitchen tips, and a touch of French joie de vivre, always full of heart!

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