How to Chop an Onion Real Fast




Introduction: How to Chop an Onion Real Fast

Almost all of my savory cooking begins with sautéed onions. I've got to dice the onions nice and evenly first. This used to take me a long time until I took a class at the Bernal Cutlery, a rad knife shop in San Francisco. I think the single most important thing I learned in this class was how to chop an onion quickly. I'd like to help you level up your veggie prep skills too!

This wizardry is possible because onions are naturally layered. If you take advantage of this geometry, you can use relatively few cuts to yield nicely diced onions really quickly.

If any of the steps in this Instructable are unclear, please take a look at the video for reference!

Step 1: Gather Your Supplies!

You will need the following things to embark upon this adventure:

  1. An onion.
  2. A knife.
  3. A cutting board.

Step 2: Split the Onion

Split your onion in half "lengthwise" - from tip to tip.

Step 3: Trim the Onion

Cut the pointy bit off of both halves.

Step 4: Peel the Onion

Peel off the outer skin. There's sometimes a thin translucent skin under the outer skin. Vegetables are fascinating. You can peel this layer off too.

Step 5: Planar Bisection!

This is where it gets interesting!

Keep the onion split-side-down on the cutting board. Carefully holding the onion down, slice into the onion from the trimmed face. Cut almost all the way back to the root end (but don't cut all the way through!). Pull your knife back out.

Step 6: Longitudinal Slices

Keep the onion split-side-down on the cutting board. Make a series of vertical cuts lengthwise side-by-side. Again, make these cuts almost all the way through the tail, but stop just short of cutting the onion apart.

Step 7: Voila!

Last cutting step! Take your knife and make a series of narrowly spaced slices perpendicular to the cuts you just made.

Wow! Magically diced onions appear!



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    12 Discussions

    Onions have alternating fleshy layers and transparent membranes. Even though the membrane is very thin, it contributes to the onion-y flavor. Use it.

    3 replies

    No kidding! Thanks for letting me know, I'll keep that in mind! I worry about it being a strange texture if you get it in a bite of food, though. Any tips on how to avoid this?

    If the onion will be cooked, it shouldn't be a problem. That said, I like to remove the membrane when the outer layer of the onion needs to be removed during peeling. (It's a pedantic symmetry thing, but you can blame your concern, too and be fine.)

    i only remove the outside membrane to give the outside of the root a good grip.

    My mother-in-law Departed had another method did a similar result but didn't require chopping up the entire onion. She would bisect the onion between the root and the stem Cut off the roots and stems ,leaving a little flat surface. These cuts help keep the onion stable on the cutting board. With the larger round circle facing opward criss cross down part way through the onion. And then turn the cut face vertically and slice all the way through at desired thickness, and off come diced onion but only as much as you want to use for any particular dish. That makes it easy to store the rest of the onion if you're not using it right away.

    1 reply

    Thanks for sharing this tip! I think I'm following along in my mind - I can see how that approach would let you easily store uncut onion. I usually use up onion pretty quickly and don't usually have leftovers, but I'll keep your advice in mind for the future!

    Thanks for this! I had recently improved my onion-fu, but this will make me much better. Many thanks.

    1 reply

    Awesome! I'm really glad to hear that you found it helpful. Any feedback on how I could have documented this more clearly?

    two thumbs-up for a McFadden & Whitehead background music "Ain't No Stoppin' Us Now"....I feel the groove while choppin'

    1 reply

    Hell yeah!! It was playing when I was prepping for the video so I figured it'd be a good encouraging background track :)