previous next

Frying Onions

posted in Vegetables and Beans, Vegetarian by Kathy Maister
difficulty rating

Frying onions inevitably results in someone saying “what smells so good”?

I’m going to show you how to fry onions two ways. First, we’ll fry (or “sauté”) the onions very quickly on a high heat. Second, we’ll “caramelize” the onions, which means frying them very slowly on a very low heat.

Sauteed Onions & Caramelized Onions

Sautéed onions have a slightly crispy outside and a very soft center. Caramelized onions are very soft and very sweet. You don’t need to add anything to make them sweet, since the natural sweetness of the onion develops through the slow cooking process.

This post is going to be a slightly longer than normal, since I am going to be showing you two different techniques.

Both approaches to cooking the onions require the same ingredients to start: – onions, butter, olive oil and salt and pepper.

For 2-to-4 servings of the sautéed onions you will need:

  • 2 Tablespoons of olive oil, butter, or a combination of both
  • 4 medium onions
  • Salt and Pepper

I have already discussed how to peel an onion, as well as how to slice an onion. Because we are slicing so many onions you may want to stick them in the refrigerator for about 20 minutes before you start peeling and slicing them. That way, they won’t bother your eyes as much.

Using a sharp knife, slice the onions into ¼ inch, or smaller, slices.

Melt the olive oil or the olive oil & butter combination, in a very large fry pan over medium high heat. Be careful not to burn the butter! If it starts to smoke, turn down the heat!

Add the onions.

Quickly cook the onions, moving them around the pan with a wooden spoon or spatula. It should take no more than 10 minutes at the most for the onions to get nicely browned.

These onions are great on hamburgers, steaks, mashed potatoes or just as a delicious side dish.

How to Make Caramelized Onions

To make caramelized onions you will need time but not a tremendous amount of cooking skill. You will also need:

  • 2 Tablespoons butter
  • 2 Tablespoons of olive oil
  • 3 pounds of onions
  • 1 teaspoon salt
  • ½ cup of dry white wine or water
  • Grated Parmesan Cheese

By the time you finish caramelizing the onions they will have cooked down to about half their size.

Peel and slice the onions.

In a really large fry pan melt the butter and olive oil over really low heat. Add the onions to the pan

Sprinkle on 1 teaspoon of salt.

Cook the onions over the lowest heat possible for about 1 hour. (Yikes! That’s a long time!) Don’t be tempted to increase the heat. You can not speed up this process. Over the course of 1 hour they should not turn brown. Be sure to give them an occasional stir. This is what they will look like after 15 minutes of cooking.

This is after 30 minutes of cooking.

This is after 45 minutes of cooking.

After about one hour increase the heat to medium and cook, stirring constantly, until the onions are well browned. That could take another 25 minutes. There will be a lot of brown bits stuck on the bottom of the pan. Those bits are full of flavor. To get them off the bottom of the pan and incorporated into the onions turn off the stove and pour ½ cup of dry white wine (or water) into the pan.

After the wine is added turn the stove back on. This will ensure the alcohol doesn’t catch fire and flame up.

The wine will dissolve all the bits and make the onions even darker.

Now remove them from the heat. Add salt and ground pepper and even a sprinkle of grated Parmesan cheese.

Caramelized onions are great on their own or can be added to stews and sauces.


Adapted from: Joy of Cooking

Sauté Onions Ingredients:

(2-4 Servings)

  • 2 Tablespoons of olive oil, butter, or a combination of both
  • 4 medium onions
  • Salt and Pepper

Caramelized Onions Ingredients

(makes about 4 cups)

  • 2 Tablespoons butter
  • 2 Tablespoons of olive oil
  • 3 pounds of onions
  • 1 teaspoon salt
  • ½ cup of dry white wine or water
  • Grated parmesan cheese

If you are new to startcooking, or are a regular visitor here, please consider subscribing for free.


Ken said:

Very interesting method of cooking onions, will have to try the caramelised method. Another alternative for the sauteed onions, instead of salt add Soy sauce while cooking. I add about a 1/4 cup, which not only enhances the colour but the flavour.

Kathy Maister said:

Thanks Ken! I’ll have to give soy sauce a try!

Jun said:

Great blog! I just bookmarked it! Now I’m going to the kitchen to start cooking! lol Thanks, Kathy!

Kathy Maister said:

Good Luck Jun! I hope you don’t get too teary-eyed from cutting all those onions!

Fleagirl said:

Kathy–love your blog. I’ve borrowed your gorgeous pic of your caramelized onions for a post of my own, but linked it to this page…and sang the praises of your blog. Let me know if you would prefer me not to use the pic. Cheers!

Kathy Maister said:

Hi Fleagirl, Borrowing pics seems to be the way of the internet. As long as startcooking is listed as the source…be my guest!

Pino said:

Very interesting! I will try next time mixing the olive oil and the butter.

When I prepare them, I just fry the onions with olive oil and when they are almost done, I add brown sugar.

Kathy, very nice your suggestions. Thank you!

Kathy Maister said:

Hi Pino, It does take quite a bit of time to bring out the natural sweetness of onions. Adding sugar certainly does speed up the process! Cheers!

Moo said:

Hmmm I’m new to cooking and not very good at it, I always seem to burn everything and nearly set my kitchen on fire once making pop tarts in the toaster. but everyone insists I must keep trying. I’m making traditional sausage and mash tonight for a family meal, off to try your method… fingers crossed lol

Kathy Maister said:

Good Luck, and keep the fire extinguisher handy!

Terrymac said:

This really works! You just put a whole finely sliced onion in a pyrex bowl (I tried using a plastic bowl but it melted!) with a knob of butter. Zap in the microwave for a minute on high then stir. Repeat this process (it took around fifteen goes in my microwave) until they begin to colour in the middle then do a couple more times in 30 second blasts until they are evenly coloured. Leave to drain and cool on kitchen paper to crisp up or just add water to use as a base for onion gravy.

It might sound long winded, but it’s a lot faster than frying in a pan and you can get on with other things in between without coming back to a burnt offering!.

Jessica said:

Hello Terrymac,

Thanks for the tip on microwaved onions — always great to have another option!


Andromeda said:

Thanks so much! You taught me how to slice/fry onions!! Thank you! said:

That’s great Andromeda!
Just in case you missed it, I have a video on cutting onions as well!

squireftw said:

Amazing recipes

Dorothy said:

This was great. Does anyone have a recipe for the onions that NY City street vendors put on their hot dogs?

startcooking said:

I have not idea what the secret is of the NYC street vendor onion recipe but the aromas alone are to die for!

Shelly said:

Can the carmelized onions be reheated and served several hours after preparation?

startcooking said:


Gerard said:

Great website. How long will caramelised onions keep in a sealed sterilised glass container? Is it necessary to refrigerate the product immediately or only once the container is opened?

Cat said:

Absolutely refrigerate them – you WILL make people very sick if you don’t. I took a food handling course and it was stressed that people often think that cooked onions aren’t a big deal to refrigerate but they are. Bacteria grows very quickly on fried onions. Eat it, keep it properly heated or refrigerate (let it cool down in the fridge uncovered so you get the temperature down fairly quick) it but don’t let it sit around on the counter.

startcooking said:

Hi Gerard,
I do believe you are talking about storing carmelized onions which you have “canned”. Alas I have never done any canning so I am afraid I really can not answer your question. I did just Google Canning Onions and there are tons of web sites that offer great tips on how to go about canning onions. Good luck and thanks for the kudos!

Cat, you are so right about how important it is to store food properly. One can become very ill, very quickly from eating food which has not been properly stored.


Cindy said:

I always wanted to know how to carmelize onions. I have heard that they taste much different when prepared that way. I will use your method. Thanks

More content