Today, let’s look at a technique for how to chop an onion that’s safe, fast, and easy. I’m also going to discuss the best all-purpose onions for cooking, as well as how to reduce those pesky onion tears. In no time you’ll be chopping onions like a pro!
If you’ve been wanting to learn how to chop an onion, you’re not alone! Chopped onions are a key ingredient in so many recipes, so this is one of the most important kitchen techniques you can master.
I’ll never forget the time, years ago, when I was tasked with caramelizing 50 pounds of onions for a catering event. I had no idea my eyes were capable of producing so many tears, and after awhile, I became numb to the burning sensation and my clogged sinuses.
The good thing about that day was I had a great opportunity to improve my chopping speed and technique. And I learned a few tricks along the way.
How To Chop an Onion
In order to properly chop an onion, you need to know the difference between the root end and stem end, which I’ve shown in the photo below. The root end has little stringy roots, and it’s the side that holds the onion layers together while you chop. The stem end should be sliced off to create a flat surface.
Tip: Anytime you’re cutting a round ingredient, create a flat side for stability, which will prevent it from rolling around on the cutting board. This will make things easier and prevent injury.
1. Remove The Stem End
Using a sharp chef’s knife, slice off just enough of the stem end to create a flat side to place down on the cutting board.
See how my fingers holding the onion are tucked under, and the knife is leaning against my knuckles for stability? That’s important. Also pay attention to how my right hand is gripping the knife, with my pointer finger and thumb on the blade instead of the handle. This is the proper way to hold a knife, giving plenty of control while ensuring you won’t lose your grip. Most people only hold the handle of the knife.
2. Slice Onion in Half Through The Stem End
Place the flat side of the onion on the cutting board. Slice through the root end from top to bottom. Peel away and discard the onion skin.
3. Slice The Onion
Place both flat sides of the onion on the cutting board to limit the release of tear-causing fumes. Move one half aside. Holding the other half firmly, make lengthwise cuts, slicing all the way to the root end (without slicing through the root itself).
Adjust the angle of your knife as you slice across the onion, following the round shape. The thinner the slices, the smaller the onion pieces will be. Once again, pay attention to how I’m holding the knife and securing the onion against the cutting board.
Move your fingers out of the way as needed, creating slices through the onion until you reach the end.
4. Make Crosswise Cuts
Next, tuck your fingers under and make crosswise cuts, using your knuckles as a guide for the knife. Again, the thinner the slices, the smaller your chopped onion pieces will be.
Keep moving your guiding hand and fingers back, then grip the root as you come closer to the end.
Once the onion is chopped, you can optionally run your knife through the pieces to make them smaller. Then repeat this process with the other half of the onion.
Tip: Practice chopping onions slowly at first until you become more comfortable with how to hold the knife and the slicing motions. Your speed will naturally increase over time.
How To Chop an Onion Without Crying
“The sharper the knife, the less you cry.” Have you heard that phrase before? There’s truth to it! Using a sharp chef’s knife is the first step to reducing tears. Duller knives mean more enzymes are crushed while slicing, releasing more fumes and irritants.
Since not every home cook has a very sharp knife, the second best thing you can do is keep the exposed sides of the onion against your cutting board. That will help prevent fumes from releasing into the air. Wipe down the cutting board down with a towel as soon as you are finished.
Can I Chop An Onion in Advance?
You can chop an onion and store it in the refrigerator in an airtight container or resealable plastic bag for 1-2 days. Eventually the onion will develop a stale smell, which is when it’s time to discard it and start fresh.
Which Onions Are Best For Cooking?
Yellow onions are the best all-purpose option for cooking. They add a wonderful flavor to soups, sauces, stews, and most other savory recipes. Yellow onions are also the traditional choice for caramelizing. If a recipe doesn’t specify which type of onion to use, yellow onions are always the safest bet.
More Ingredient Tutorials
Check out my articles on How to Cook Bacon in the Oven, How to Measure Flour Correctly, and How to Roast Garlic!
How to Chop an Onion
- 1 onion
- Place the onion on a cutting board with the stem end pointing to the side. Holding the onion firmly with one hand, use a sharp chef's knife to slice off the stem end to create a flat surface.
- Place the flat surface against the cutting board and slice through the root end from top to bottom.
- Peel away and discard the skin, then place the cut sides down on the cutting board to minimize the fumes.
- Take one half of the onion and make lengthwise cuts, slicing all the way to the root end (without slicing through the root itself). Adjust the angle of the knife as you slice, following the round shape. Move your fingers out of the way as needed, creating slices through the onion until you reach the end. The thinner the slice, the smaller the final pieces will be.
- Next, make crosswise cuts, using your knuckles as a guide for the knife. Keep moving your guiding hand and fingers back, then grip the root as you come closer to the end.
- Once the onion half is chopped, you can optionally run your knife through the pieces to make them smaller. Then repeat this process with the other half of the onion.
- Use chopped onion immediately or store in the refrigerator, in an airtight container or resealable plastic bag, for 1-2 days.
Please read my full post for additional recipe notes, tips, and serving suggestions!
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What a great tutorial to prevent accidents. This is wonderful!
Except for slicing across the onion. That’s a silly thing to do if you don’t want to cut yourself.
Jennifer Farley says
Hmmmm, which slice across the onion do you mean? There are quite a few. This is the way I was trained to cut them when I worked in restaurants. Obviously you want to go slowly if you’re just starting to learn knife skills. Also, choke up on the knife so you have more control :)
Chopping is definitely not my forte, so thanks for these tips!
My daughter stumbled across this method and insisted it was now all the rage and the “proper” way to chop an onion. It’s not at all how I was taught by my grandma oh, about 40 years ago, But, I tried it. I really did give it a go but I found this method to be clumsy and counterintuitive (especially getting the skins off) and much more difficult than how I was taught. After chopping about a million onions in my life (lol), I think I’ll stick with the original way. :)
I definitely agree with you on the virtues of a sharp knife!
Jennifer Farley says
Whatever you think is the easiest, most effective way is definitely the best for you! I was taught the classic technique in school, but was taught this by a sous chef once I was settled in at my first restaurant. For me, there was no going back! So this is the technique I always teach people now. But if you have a way that is more effective for you, ignore me :)
Ignore you!? No way!! I love your site! :)
Let me make a suggestion:
You slice the onion (point 3) and then make crosswise cuts (point 4).
Invert these two steps. First cut crosswise to obtain slices as thin as you want. Stack 3 or 4 of them and cut them to your liking.
The difference is that you don’t make diagonal cuts; all are against the table.
I do it this way.
Jennifer Farley says
That will certainly get you nicely chopped onions! I find it easier to keep everything attached to the root.
I’ve been chopping onions for over 50 years , similar to this but it never occurred to leave the root end on, controls the cut pieces .
Thanks for the tip
Jerry Garcia says
I learned you never cut the stem end, it’s where all the tear causing chemicals are. Cut the root off, remove skin, place onion with stem end on board and cut side up, cut lines from top to bottom leaving about half inch from stem uncut, rotate onion a quarter turn and cut from top to bottom again, now place onion on side and cut top to bottom again. Perfect cube cuts with no tears.