How to Cut an Onion (& Why Different Cuts Actually Matter)

There are as many ways to cut an onion as there are to skin a cat. Actually, no, cutting an onion is way simpler than skinning a cat. Below, Nozlee explains if cutting an onion a specific way even matters (it does), why you might choose to cut it into different shapes and sizes (to control its cook rate), and how to do so the right way (“right” as in the way all your fingertips remain intact). 

But does it really matter how I cut an onion?

When Table for One columnist, Eric Kim, saw this article on the editorial calendar, he was proud to report to the editorial team that he had no method whatsoever. He slices an onion one way, turns it around, slices it the other way, and there you go, chopped onion.

But let's use this Braised Onion Sauce as a case study. In the recipe, Kenzi calls for onions to be sliced into 1/4”-thick half-moons. But, let’s say, we cut 1”-thick slices instead. The cut surfaces exposed to the pan—or, the parts of the onions that will soften, brown, and caramelize quickest—would make up a much smaller percentage of the onions in the pan. After braising for an hour, the centers of each onion slice would be cooked less than if they had been cut to ¼”-thick slices. Conversely, if we cut 1/16”-thick slices, the onions will caramelize much quicker in the prescribed hour. The final texture of the sauce would be jammier, closer to a puree. So, how you chop does kind of matter.

That being said, chopping an onion isn't rocket science—in fact, it's one of the first things you learn in the kitchen. Whether you're a first-timer or an old hand, today we have a primer on the various ways to chop an onion: dicing, slicing (two ways!), and a coarse chop. Our co-founder, Merrill, who seems to be in the same onion boat as Eric, said: "It doesn't really matter how you cut an onion, but if you don't do that right, why do anything right at all?" We agree.

One thing we don't have an answer to is how to avoid teary eyes while chopping. Advice runs from the sensible-sounding (keep the root end, which contains most of the compound that makes your eyes water, as intact as possible) to the silly (chop with a piece of bread in your mouth, or wear special goggles).

Let's get chopping! the different cuts are:

Dice (Large, medium, and small)

As seen in: Individual Sweet Potato Gratins with Crème Fraîche, Onions, and Bacon

When you're stumped for what to make for dinner, dicing an onion is never a bad place to start. By the time you're done, you're likely to have an idea about whether it'll be soup, a frittata, or anything else. Whether large, medium, or small dice, the approach is very similar. Diced onions, like roughly chopped onions, are used for a prominent, but consistent onion flavor and texture (chunks of similar-ish shape and mass are more likely to cook at the same rate and in the same way). Sharpen your best knife—a sharp knife is actually less dangerous than a dull one, which you can easily lose control of— and let's get started.

1. Peel and Prep. First things first: halve the onion through the root and tail ends. Chop off that tail end and discard, then remove all traces of papery skin.

2. Cut Horizontally. Being careful not to cut your hands, make 2 to 3 horizontal cuts through the onion, stopping before you reach the root—again, a very sharp knife helps with this! What's the point of this step? You're cutting through the curvature of the onion's surface, making for evenly square pieces of onion when you finish.

3a. Cut Vertically. Cutting from just before the root to the tail end, make 5 to 6 straight cuts perpendicular to the horizontal ones. (Don't worry too much if slices on the side start to fall off because your cuts are too deep; hold them together with your fingers and keep going.)

3b. Or, Cut Radially. Our Genius Recipes columnist, Kristen's brother, Billy, prefers radial cuts when dicing his onions—i.e. angling along with the curve of the onion—which he claims makes for a neater dice afterward. We tried it and found the results to be more or less the same, but it certainly doesn't hurt to get geometry involved!

4. Ready to Go! After being cut every which way, this onion is ready for its final destiny.

5. Final Dice. Starting at the tail and moving toward the root, cut across the onion to make tiny, evenly-sized pieces of onion: a true dice. (I look like I'm about to cut my fingers off in that first photo. Rest assured that I still have all 10 of them.)

6. Discard The Root. And that's it—sauté-ready diced onions.

Slice (Half-Moons)

As seen in: Cider-Braised Pork Shoulder with Caramelized Onion and Apple Confit

There are two ways to slice an onion. The first is easiest, and it's what you look to when pickling onions, topping a pizza, or slicing up chili garnishes. The half-moon shape gives the "face" of each onion slice maximum surface-area, and so is also conducive to browning.

1. Peel and Prep. The first steps are the same: halve the onion, cut off the tail end, and peel it. Rest the halves flat-side-down.

2. Slice Away. Pushing the knife down and forward, make evenly-spaced slices, finally ending at the root. If the recipe calls for anything thinner than 1/8” slices, I will usually switch over to a mandoline. 

Slice (Radial-ish)

As seen in: Braised Onion Sauce

When you're looking to caramelize a batch of onions— to top mashed potatoes, garnish polenta, or make classic French onion soup—you should slice a little differently. The method above produces unevenly-sized slices, which means that after 30 minutes or more of slow caramelization, some of those slices will have entirely dissolved while others will still have their shape. For even cooking, it's best to slice a little differently: just turn your onion a quarter turn before going at it.

1. Peel and Prep (and Cut Off the Root End). For this preparation, you'll want to cut off the root end of your onion as well when prepping it. Then with the root and tail parallel to your knife, start at one side and start slicing away.

2. Ta-da! See? Same-sized slices ready for a long, slow session in the skillet.

Rough Chop, Fine Chop, and Mince

As seen in: Traditional French Cassoulet, Creamy Tahini Potato Salad, Sausage Stuffed Mushrooms

Sometimes, the size and shape of your chopped onion doesn't matter so much, like when making kebabs or chicken stock. Like half-moons, this is another cut conducive to caramelizing (the multi-facetedness of each rough chunk maximizes surface area). We saved the easiest preparations for last!

1. Peel and Prep. The first steps are the same: halve the onion, cut off the tail end, and peel it. Rest the halves flat-side-down.

2. Like Dicing, But Not. Take everything we said about slicing vertically and horizontally and toss it out the window: simply make 3-4 cuts from root to tail, then 3-4 cuts from side to side. For finely chopped onions, make 6-8 cuts each way, and for minced onions, fan-chop the finely-chopped onions until you have tiny 1/16" bits.

This article was originally published in July 2012, and has been updated with relevant information.

What's your best anti-onion-crying technique? Let us know below in the comments.