Best Way to Chop Onions

Here's how to chop an onion quickly, safely, and without waste. It's a modification on the traditional 3-axis chop that allows you to get small, even-sized pieces of onion right up to the root end, and it's faster than any other method that I've tried.

Finding a Better Way

If you’ve been cooking for some years, you’ve probably spent untold hours chopping onions. It’s a chore, that’s a necessary evil of cooking because onions form the basis of countless dishes. The traditional way of cutting onions has never sat well with me because you end up with a chunk of onion that you either toss and waste or spend extra time chopping it separately. That’s why I’ve spent the past few weeks dissecting onions to figure out the best way to chop them. While I can’t say I’ve found a way to take all the hassle out of chopping onions, I have found a significantly better technique to chop them.

Onion Anatomy 101

Before I show you the ultimate onion chopping technique let’s get on the same page about an onions anatomy and some basic terminology. Onions are essentially a layered sphere with a root end and a top end.

When you cut an onion in half, it exposes the layers, and you can see the core in the center.

How to Prep an Onion

When you want to chop an onion, the first thing you have to do is to prep it. There are a lot of ways to do this, but the most efficient method is the following:

Cut the top off.

Slice the onion in half from the top to the root end.

Peel the halves.

The reason why we don’t cut the root end off is that this, along with the core of the onion, is what’s going to hold our onion together as we chop it.

Traditional Method of Chopping Onions

This is the traditional method of chopping onions that most chefs use. It’s certainly not the worst method, but it’s not perfect either.

Slice vertical slits in the onion from the top to the root end.

Slice two to three horizontal slits in the onion from the top towards the root end.

Turn the onion 90 degrees and chop the onion perpendicular to the first set of vertical slits.

The Problem

Here’s the problem with this technique: you end up with a big chunk of onion towards the root end that you then have to chop up separately. It may not seem like a big deal, but when you’re dealing with a mountain of onions, it’s a lot of extra work.

Some of you may be thinking that if you just cut the slits deeper, you can get all the way to the root end, but then the onion will start to fall apart as you chop it. This makes it very hard to chop the onion evenly, and it also presents a danger of cutting yourself.

A Better Way to Chop Onions

After taking apart a dozen onions, and thinking about the internal geometry of them, I realized that when sliced in half, the core of the onion isn’t sloped like the outer layers. Since it’s essentially flat, there’s no need to cut horizontal slits into it.

After realizing this, I modified the traditional method, cutting horizontal slits into the sides of the onion towards the center, instead of through the whole onion, from the top to the root end. This leaves the core intact, holding the onion together, so you can cut the vertical slits deeper without affecting the stability of the onion. This, in turn, allows you to chop the onion faster, finer, and more evenly. Here’s a video on my full onion chopping method, and you can you scroll down a bit more for my step-by-step process with photos.

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5 from 2 votes

Best Way to Chop an Onion

Course Basics

Ingredients

1 onion

Grams + US Cups - US Standard

Instructions

Prep the onion using the instructions above
Cut two to three slits from one side of the onion towards the center, but do not cut through the core.
Cut two to three slits from the other side of the onion towards the center, leaving the core intact.
Cut vertical slits into the onion almost to the root end. The closer you space these slits, the smaller your onions will get chopped.
Turn the onion and chop perpendicular to the vertical slits you just made, all the way to the root end.
Flatten the root end and trim any remaining onion off the root.

QUESTIONS or COMMENTS?

Comments

Wendy says

01/07/19 at 07:46

Yay! Great stuff!

- Marc Matsumoto says
  
  01/07/19 at 08:27
  
  Thanks Wendy!
  
  - Jim says
    
    01/08/19 at 00:28
    
    As always, appreciate your ideas, creativity, shortcuts and unbounded enthusiasm for all things tasty.
    
    - Marc Matsumoto says
      
      01/08/19 at 10:32
      
      Thanks Jim, and I love the phrase “unbounded enthusiasm”, sounds much better than “out of control food fanatic”. 🤣
      
  - Trudy says
    
    01/08/19 at 02:10
    
    Works for me! After all these years of tears!
    
    - Marc Matsumoto says
      
      01/08/19 at 10:30
      
      Glad to hear it! 😄
      
Robert says

01/08/19 at 00:22

There’s absolutely no reason for the horizontal slits. If you look at the way an onion is constructed, you will understand that. All you need are the vertical slits and then chop down. Your onion will be nicely chopped.

- Marc Matsumoto says
  
  01/08/19 at 10:35
  
  Hi Robert, I’m sorry if my explanation didn’t make this clear, but it’s because of the way an onion is constructed that you need the horizontal slits. If you look at the way an onion is layered, the parts of the onion towards the sides are nearly vertical, which means cutting vertical vertically in two directions will yield long pieces (you need to cut on the horizontal axis to break these up).
  
- Nathan Krowitz says
  
  08/19/19 at 23:59
  
  What about the outer edges?
  
  - Marc Matsumoto says
    
    08/21/19 at 09:56
    
    Hi Nathan, the outer edges cut sliced first.
    
Diane says

01/08/19 at 01:03

👍

- Marc Matsumoto says
  
  01/08/19 at 10:31
  
  😁
  
John says

01/08/19 at 01:45

Who would have ever thought. You are amazing!

- Marc Matsumoto says
  
  01/08/19 at 10:30
  
  Thanks John!
  
Emma says

01/08/19 at 05:48

I hope you didn’t cry 🙂 Thanks for the tip, Marc

- Marc Matsumoto says
  
  01/08/19 at 10:30
  
  Hi Emma, this doesn’t reduce the amount of volatile sulfur compounds (the stuff that makes you cry) released while chopping. What will help is to chill your onions. I store mine in the fridge.
  
Mirta says

01/08/19 at 06:40

From niw on I will cut my onion lije you. Thank you

- Marc Matsumoto says
  
  01/08/19 at 10:29
  
  Thanks! I hope you find it as effective as I have.
  
Peter Shemonsky says

01/08/19 at 15:55

Been doing it wrong for years, thanks for the Hack, love your enthusiasm (and you didn’t even cry)

- Marc Matsumoto says
  
  01/08/19 at 22:29
  
  You’re welcome! The trick to not crying is to chill your onions. I store mine in the fridge.
  
Mercy says

01/09/19 at 06:07

Thanks for the video. I wash my onions in very cold water, dry them before chopping, no more tears.

- Marc Matsumoto says
  
  01/09/19 at 08:56
  
  Good call, the lower temperature slows the release of the volatile sulfur compounds in onions that makes you cry. You can also get the same effect by storing your onions in the fridge.
  
Maggie says

01/09/19 at 06:36

I REALLY wish the air slash worked, though – it looks like it made you very happy!

- Marc Matsumoto says
  
  01/09/19 at 08:58
  
  🤣 Me too! I was so happy because that was probably my 10th attempt.
  
Jade says

01/10/19 at 03:49

My method is ALMOST like the one you’ve mentioned! Will try it your way while preparing lunch tomorrow

- Marc Matsumoto says
  
  01/13/19 at 15:11
  
  I hope it worked out!
  
Thomas C. Kaylor says

02/08/20 at 02:41

Thanks for that how to. Now a cave man can do it

- Marc Matsumoto says
  
  02/08/20 at 10:32
  
  😆You’re welcome!🍖
  
mary says

06/04/20 at 06:37

thanks !!!!

- Marc Matsumoto says
  
  06/04/20 at 09:05
  
  You’re welcome Mary!