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Learning how to dice an onion was honestly, truly the best thing I learned after weeks and weeks of intensive culinary school programs. Sure, I learned how to debone a fish, roast a chicken, cover a cake with fondant and all of the essentials of fine cooking, but the one thing I turn to again and again is the knife skills I developed from those courses. Particularly when it comes to dicing an onion.
This technique keeps the onion intact until the very end, so there’s no fighting to keep all the pieces together as you chop. As a result, you make fewer cuts into the onion, releasing less sulfurous gas, so your eyes are less likely to sting and water—or so I’ve been told. I don’t entirely know if that’s true, but I do know that this method takes so much of the hassle and annoyance out of chopping onions. So you can get to enjoying dinner faster.
How to Dice an Onion, in Four Steps:
Step 1: Cut the onion in half along the root.
Peel the papery skin off the onion, and find the little hairy nub on one end. That’s the root. Slice the onion in half, cutting right through the root. That will hold each half’s onion layers together as you dice, so this step’s crucial.
Step 2: Make two horizontal cuts into the onion.
With the onion flat on the cutting board (so the cut side is down), hold your knife as if it’s resting on the board too. Instead of chopping up and down, like you normally would, you’re going to make two cuts into the side of the onion.
Find the side opposite the root, and make one cut into the side of the onion, about 1/3 of the way up. Don’t cut all the way through the onion; stop just before hitting the root. Make a similar cut a little bit higher up, about 2/3 of the way.
Step 3: Cut “fingers” into the onion.
Now you’re ready for some traditional cutting. Hold the knife like you normally would, with the blade facing down toward the cutting board. Point the tip of the blade toward the root of the onion and cut long, narrow slices into the onion, stopping just before you hit the root. The cuts will look almost like fingers or fringe.
Step 4: Dice, dice baby.
Now, you want to cut through the onion in the opposite direction, creating little cubes of onion-y bits. Stop just before hitting the root, and discard that little nubbin. Voila!
