It bugs me that I've just sort of self-taught a method of turning a whole onion into a nicely diced pile. I'm going to assume my method is inefficient and wasteful.

Could someone explain how I should be dicing a whole onion?

Unusual and clever methods also appreciated!

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    Good question! The "official" sources always instruct to cut the onion in half then radially and then turn it and cut across the radials. With radial cuts the chunks on the outside edge of the vegetable are much larger than those on the inside. Vertical slices, instead of radial, produce much more consistent results for me. I'm hoping an expert answers this one. Oct 15, 2010 at 13:33
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    @Sobachatina - the last time I had a chef show me how to do it, he cut vertically rather than radially, as you say.
    – justkt
    Oct 15, 2010 at 13:40
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    @justkt - Thanks! I will gladly accept your anecdotal evidence suggesting that I'm not insane. Oct 15, 2010 at 13:52
  • At some point, I heard that the vertical method was the "classic" way to cut, and radial cuts were the "new" way. Or, maybe I have that backwards...
    – Bob
    Oct 19, 2010 at 18:57
  • I don't have a definitive way, but using a very, very sharp knife and making sure you are using the slicing movement instead of just pushing the edge through the onion makes for cleaner slicing, instead of some crushing, and makes it easier on the eyes. Oct 21, 2016 at 15:36

1 Answer 1


First, remove some, but not all, of the end. Make sure to leave a little of the root intact, as this will make the next steps easier. Peel the onion and discard the peel.

Stand your onion on one of the now-flat ends. Chop in half with your chef's knife.

Lay a single half on the flat end. Working from root to cut end, make several cuts at dice width that cut almost to the root end, but leave a little bit still attached.

Working perpendicular to your last set of cuts, make another set of cuts at dice width. This will leave you with cut pieces. When you get to the portion with the root, discard it.

Repeat for your other onion half.

During cooking, the layers should flake apart leaving dice sized pieces.

  • 4
    Alternatively, retain the peel for adding colour and flavour to stocks and sauces. The peel freezes perfectly well.
    – daniel
    Oct 15, 2010 at 14:21
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    See this demonstrated by Jamie Oliver. It differs only slightly from how Gordon Ramsay recommends. IMO, leaving the root is a hassle, and still burns my eyes.
    – zanlok
    Feb 8, 2011 at 19:57
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    Peeling is easier if you chop it in half before the peeling May 24, 2011 at 17:00
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    I've seen a few cooking shows where they tend to slice the onion vertically before slicing it horizontally ... I find it much easier to go the other way ... a few horizontal slices, and then slice vertically across almost the whole thing. I've also been known to slice diagonally one way, then the other, rather than horizontal & vertical.
    – Joe
    Oct 21, 2016 at 1:54

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