This Is the Safest and Fastest Way to Dice an Onion, and Almost No One Teaches It

Onions are one of the first things any aspiring cook should learn to cut. Whether you’re dicing them into large chunks for soups and stocks, or mincing them small for refined sauces or even salad dressings, chopping an onion is an essential kitchen skill. But there’s the most common method most people know, and then there’s the easier and safer method few do.

The most widely known method for dicing an onion goes like this: Set a halved onion on a cutting board and first make a series of downward cuts through the onion (but not through the root end). Then make a series of perpendicular cuts in toward the root end while holding the knife blade’s flat side parallel to the cutting board.

Those horizontal cuts—where the knife runs parallel to the cutting board—are, well…dicey. Nobody likes those cuts. It’s awkward and risky, requiring you slide the blade just under and towards your non-dominant hand that is sitting on top to hold the onion stable. A slip of the hand on a slick onion can send you searching for a band-aid.

Despite the challenge and risks, that is the basic cutting technique taught to most home cooks and chefs alike. Instead, I swear by an alternate method that requires none of those parallel-to-the-cutting-board horizontal slices. I first saw this method years ago during my very first class at the Culinary Institute of America. It wasn’t part of the official knife-skills curriculum—just an off-the-cuff demo from my instructor, Chef James Jennings. But it stuck. Even after years working in professional kitchens, this is still my go-to method: safer, faster, and just as precise.

If you’re dicing several onions at once, you don’t need to constantly reposition your knife hand for different slicing orientations. You’re always cutting the onion in the same direction: down towards the cutting board. While I by no means invented this cutting technique, I’ve been preaching its gospel whenever and wherever I can. I’ve converted recipe developers and editors at other major food publications to it (one of my former coworkers even made a viral social video about the method!).

In any event, now I present the steps for you so that you too can adopt a safer and more efficient method of cutting onions.

Step-by-Step: The Safer Onion Dice

Step 1. Halve the onion through the root end and peel it. Working with one half at a time, make a series of evenly spaced vertical cuts from pole to pole (top to root), slicing down toward the cutting board but stopping just before the root end. Use a claw grip with your non-dominant hand, letting your knuckles guide the knife while your fingertips and thumb stay safely tucked away.

Step 2. Go back and extend the center cut to divide the onion half into two even quarters.

Step 3. Flip quarters onto newly cut sides, then align quarters so that vertical cuts are now horizontal.

Step 4. Now make a second series of evenly spaced pole-to-pole cuts down towards the cutting board; once again be sure to keep the root end attached.

Step 5. Finish by making a series of evenly spaced vertical cuts perpendicular to the previous ones, once again using the knuckles on your non-dominant hand to guide the last set of knife strokes. You should have diced onion pieces. 

Step 6. Repeat with the remaining onion half.