How to Dice an Onion

By ShowMeStepByStepPublished Updated

Based on a video by Chef Jean-Pierre.

A clean, even dice on an onion transforms a dish. Unevenly cut onion either burns before the thick pieces cook, or leaves you chewing through raw chunks.

This walkthrough is based on a tutorial by Chef Jean-Pierre. His method skips the traditional horizontal cut - the onion's own layers already give you the third dimension, and you end up with cleaner dice with less fuss.

Step-by-Step Guide

1

Pick a Good Onion

0:10
Step 1: Pick a Good Onion

Start with a good onion: heavy for its size with tight, papery skin that's still whole. A light, soft onion has already started to break down inside and won't dice cleanly.

Press the onion gently. It should feel firm, almost hard. If it gives, pick another.

Tip

Yellow onions are the all-purpose workhorse. White onions are sharper; red onions are milder and better raw.

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2

Trim the Tip and Root

0:50
Step 2: Trim the Tip and Root

Trim a thin disc off the tip and the root of the onion. Hold a paring knife blade-out and turn the onion into the blade rather than pushing the blade toward your hand - safer, and more control.

Keeping just enough of the root for now means you still have something to anchor the halves when you cut later.

Tip

Don't cut off too much root - you'll want some left to hold the onion together when you dice.

3

Peel the Skin and First Layer

2:05
Step 3: Peel the Skin and First Layer

Score the papery skin down one side and peel it off. While you're at it, peel off the first fleshy layer underneath. It's slippery and doesn't dice cleanly - better gone.

You should be left with a bare, smooth onion.

Tip

Save the peels for stock. Onion skins give homemade broth a deep golden color.

4

Halve the Onion With the Grain

2:40
Step 4: Halve the Onion With the Grain

Look at the onion and notice the thin lines running from root to tip. Those are the grain. Halve the onion with the grain - meaning cut from root to tip, not across.

This single choice is what gives you clean, even dice later. Cut across the grain and your dice fall apart into mush.

Tip

Use a sharp chef's knife and one clean stroke. Sawing back and forth crushes the onion cells and wakes up the tear-inducing compounds.

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5

Make Vertical Cuts, Keep the Root Intact

3:15
Step 5: Make Vertical Cuts, Keep the Root Intact

Lay a half flat-side down. Make vertical cuts along the grain, stopping just before the root end so the onion stays held together. The cuts should be as close to each other as the dice size you want.

Fingers curled back, knuckles leading. The root anchor is what keeps the whole thing from collapsing as you work.

Tip

Closer cuts give finer dice, wider cuts give bigger chunks. Match the cut spacing to what the recipe wants.

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6

Cross-Cut to Dice

4:20
Step 6: Cross-Cut to Dice

Rotate the onion 90 degrees and slice across the vertical cuts. The pieces fall away as perfect cubes - no horizontal cuts needed, because the onion's own layers gave you the third dimension already.

When you get near the root end, chop that leftover piece on its own. Done.

Tip

If the onion starts rolling, flip it so the flat cut side is down. A stable onion is a safe onion.

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❖ The Recipe

How to Dice an Onion

Serves
Yields about 1 1/2 cups diced
Prep
3 min
Cook
0 min
Total
3 min

Ingredients

3 items
  • 1 largeyellow or white onion
  • 1sharp chef's knife8-10 inch blade works best
  • 1, stablecutting board

Nutrition

estimated · per servingEstimated from the ingredient list, not measured. Actual values vary by brand, preparation, and serving size. Not a substitute for measured nutrition data.
Calories
90kcal
Protein
2g
Fat
0g
Carbs
21g
Fiber
4g
Sugar
10g

Method

  1. 1
    Pick a Good Onion. Start with a good onion: heavy for its size with tight, papery skin that's still whole.
  2. 2
    Trim the Tip and Root. Trim a thin disc off the tip and the root of the onion.
  3. 3
    Peel the Skin and First Layer. Score the papery skin down one side and peel it off.
  4. 4
    Halve the Onion With the Grain. Look at the onion and notice the thin lines running from root to tip.
  5. 5
    Make Vertical Cuts, Keep the Root Intact. Lay a half flat-side down.
  6. 6
    Cross-Cut to Dice. Rotate the onion 90 degrees and slice across the vertical cuts.

Your Guide

Chef Jean-Pierre

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Key takeaways from How to Dice an Onion

5 questions, answers, and one-line explanations. Tap to expand.

  1. 1.How to pick a good onion?

    Answer: Heavy + firm + tight skin

    Heavy for size with tight papery skin still whole. Soft = already breaking down inside, won't dice cleanly.

  2. 2.Why peel off the FIRST fleshy layer too?

    Answer: Slippery, dices poorly

    First fleshy layer is slippery and doesn't dice cleanly. Better gone before you start.

  3. 3.Which direction to halve the onion?

    Answer: With the grain (root-tip)

    Halve root-to-tip. Across the grain = dice falls apart into mush. With the grain = clean even dice.

  4. 4.Why leave the root END intact while cutting?

    Answer: Anchors the halves

    Root anchor keeps the whole thing from collapsing as you make vertical cuts. Stop just before the root end.

  5. 5.Does this method need horizontal cuts?

    Answer: No, layers give it

    Skip the traditional horizontal cut. The onion's own layers give the third dimension. Cleaner dice, less fuss.

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