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How to Chop an Onion

Onions add so much flavor to everything from breakfast hash to dinner casseroles. Here’s how to chop an onion.

A chopped onion is shown on a cutting board next to a knife. Half of the onion is cut but in a half-moon shape and the rest is in a pile.

Got onions? This essential ingredient is a must-have in many kitchens because of the crucial flavor they supply to everything from sauces to soups, casseroles to roasts and so much more. Knowing how to chop an onion is a kitchen basic that will help you tap into that delicious flavor whenever you wish.

This tutorial can be used for any type of onion — sweet onions, yellow onions, red onions, even larger shallots. Make sure the onion is fresh and has a firm texture and dry, papery skin. Not only will it chop better, but it will taste better too.

Ready to get started?

Gather Your Tools

Begin by gathering the essential tools: a sharp knife and a stable cutting board. Both are necessary for your safety and the success of your chopping. If you are super sensitive to onion vapors, an eye covering like kitchen goggles can help too.

Prep the Onion

Trim a small slice from the top of the onion and the root end. This will give you a stable surface to make holding the onion in place easier. It will also make peeling away the layers simpler. And yes, you should now peel away the outer flavor of papery or browned onion skin.

A chopped onion is shown on a cutting board next to a knife. Half of the onion is cut but in a half-moon shape and the rest is in a pile.

Start the Cutting

Slice the onion in half from stem to root end. Working with one half at a time placed cut side down on the cutting board, make vertical cuts all the way through to the cutting board. Adjust the size of these cuts based on how big you need the onion pieces — thinner for a finer chop and thicker for a more substantial dice. Turn the onion and make horizontal cuts approximately the same thickness as the vertical cuts. Repeat with the second half of the onion.

Your onions are now ready to use in recipes. Enjoy!