How To Chop an Onion

Learn how to chop an onion easily and quickly for recipes calling for diced onions with this step-by-step tutorial. This post was sponsored by Cutco.

Did you know the world record for chopping an onion is only seven seconds? Think you can do it faster using our onion chopping guide?

Onions are in almost everything we eat (except deserts of course). There are white, yellow, and red onions. They can be sliced thin, roughly chopped, or even made to look like a flower. Onions can be caramelized or sautéed and added as the base of many dishes.

Today we are going to look into a technique to chop an onion fast, safe, and effortlessly. I’ve done a medium dice, but you could cut them finer for mince onions or do a large dice for more of a chopped onion. You’ll be all diced before your tears decide to fall out!

Why Do Onions Make You Cry?

Onions have an enzyme called alliinase that releases when the cell walls are cut. A sulfuric compound called propanethial-S-oxide (PSO) forms which makes your eyes water. This reaction can increase the more you chop, so here’s some tips to minimize the tears. 

Tips To Minimize Tears:

Whenever you chop strong onions (which in my case is any onion because my eyes are really sensitive) you’re bound to shed a few tears. There are several ways to avoid this.

1. Turn on a faucet and put your head above the faucet. I do this and, maybe I’m crazy, but it really seems to clear the fumes.
2. Put the onion in the fridge for 30 minutes before you cut it. This slows the reaction that causes you to tear up.
3. Another way to prevent tears from onions is to use a sharp chef’s knife. The knife will cut through the onion cell walls evenly, resulting in less onion fumes being released.
4. Perhaps this is a bit drastic, but you can also try onion goggles. Yes, really. These exist as a thing that you can buy.

Now, on to the chopping…

How To Chop An Onion

Step #1

Pick out your onion. Ain’t it a beaut?

Step #2

Slice off the stem end.

And slice off a thin part of the root end.

Step #3

Make a cut vertically through the middle of the root to the bulb.

A clean cut through the onion.

Step #4

Peel the skin off the onion using your fingers. If you need to, peel off the outer layer of onion if it is soggy or ugly, or if you can’t seem to get the skin off any other way.

Step #5

Once the onion is peeled, take one half and place it on the cutting board. Make vertical cuts, making sure to leave the root intact. I cut each slice about 1/4 inch thick.

Make sure you are protecting your fingertips, holding them like in the photo in kind of a claw grip, away from the blade of your sharp knife.

This is the onion after the first cuts. It should look like a fan.

Step #6

Next dice your onion using horizontal 1/4 inch cuts. These will go through the entire onion.

Step #7

Repeat with the other half of the onion and use in a recipe that calls for diced or chopped onion.

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This post originally appeared in September 2016 and was revised and republished in July 20202