Knowing how to dice an onion properly is one of the most fundamental knife skills you can learn. There are nearly endless diced onion recipes out there because onions add such great flavor, color, texture, and nutrition to a wide range of dishes.
We have been teaching this culinary skill for YEARS and have found that this is the easiest way to dice an onion.
Steps to Diced Onion Success
Start with a sharp chef’s knife to help you dice an onion without crying. We’ve also heard that running tap water, holding a toothpick or unlit match between your teeth, or refrigerating the onion before cutting also help, but some onions are just pungent and nothing seems to work! If you are really sensitive, you might look into buying onion goggles (yes, they are a real thing!).
Using a proper knife hold and a secure cutting board, chop off the stem end and trim the root end, removing the hairy fibers.
Place the onion on the flat stem end and slice in half from top to bottom. Peel.
Lay one half on the cutting board. Onions have natural lines; use these as a guide to help create even cuts. Space out the cuts based on the size dice you need. Don’t slice all the way through to the root end.
Once you reach the end, rotate the onion 90º and chop. For large dice onion pieces, space slices out farther. For finely diced onion pieces, make thin slices in both directions.
Voila! You’ve learned how to dice an onion!
Once you learn how to dice an onion like a chef, not only will you feel more confident in the kitchen, but you’ll surely impress your friends at your next dinner party!
Want to take your knife skills to the next level? Take our online knife skills 101 course!