The Pro Chef's Technique For Dicing Onions

Of all the things you want to know how to do well in the kitchen, dicing an onion might be the most important. If you've ever found yourself hacking away at a scraggly-looking bulb, producing unevenly shaped pieces that you can barely see through your weepy onion tears, you know what we mean. Nearly every savory recipe seems to call for an onion or two and not being able to dice one well is a real letdown. Fortunately, Food52 has some tips from their own test kitchen director, Josh Cohen, on the best technique for dicing onions.

Cohen has clearly overcome his own allium struggles in the past because he addresses all of our onion-related challenges: the tears, what to do with that hairy root end, and how to attain aesthetically pleasing, evenly-sized cuts. Yes, size matters! Cook's Illustrated reminds us that consistently-sized pieces will cook at an even rate and that's the key to a successful dish. Let's get started so we can finally put our amateur onion days behind us.

A sharp knife and a little prep work are the key to dicing onions

First things first, Cohen says to sharpen those knives! Not only will this help the knife slice through the onion's cells cleanly, resulting in less of that eye-scorching vapor, but a sharp knife is actually safer than a dull one. You have to apply more pressure to cut with a dull knife, making it more likely that you ill slip and put your unsuspecting fingers at risk for injury, per the University of Rochester Medical Center. Food & Wine suggests sharpening your knives with sandpaper or running them across the rough underside of a mug. Or, you can purchase a knife sharpener. Keeping all your fingers and reducing onion tears seems worth that investment.

Once your blade is sharp, you can deal with the onion root and skin. Cohen suggests barely trimming the root end, leaving enough behind to keep all the onion's layers intact. This way, as you slice and dice, your onion will hold its shape. Next, slice the onion in half through the root and tail ends, chop off and discard the tail end, and peel off the papery skin. Ok, you might think you know what's coming next – that chef-y trick that requires a zillion speedy slices in every possible direction, turning your onion prep into an origami session. But, no! Cohen simplifies things for us with just a few simple cuts.

Slice your onion in two directions and that's it

At this point, you're halfway through your onion dicing task and ready to slice. Here's where Cohen's shortcut comes in. Most chefs will advise that you make a few horizontal slices through the onion, holding your knife parallel to the board. Cohen says that's just an unnecessary extra step and Rachael Ray evidently agrees. In a YouTube video demoing her onion-cutting method (her technique appears to be the same as Cohen's, BTW!), Ray points out there's no need to cut extra layers when nature has already provided onions with plenty of them. Hey, we're all about a shortcut.

So, with your onion peeled and split in half, Cohen says to place it flat-side down on the cutting board, facing away from your body. Next, make several vertical cuts down the length of the onion, stopping before your blade gets to the root end. Remember, that root is the thing holding this whole show together, so don't slice through it. Finally, starting at the tail and moving towards the root, make thin cuts across the width of the onion and watch as neat little diced squares form before your very eyes. That's it! Is it just us, or do pro-chef-level onions deserve a post on Instagram? We're thinking yes.