How to Thinly Slice an Onion

Slicing onions is a task many people dread or avoid entirely. However an evenly sliced onion is a great addition to many dishes and can entirely change the texture and flavor when cut to a specific thickness. With some setup and careful technique, slicing onions even thinly, is not the onerous task one would expect.


  1. Image titled PlaceFreezer Step 1
    Place the onions to be sliced in the freezer and leave them there for about 15-20 minutes. Let them sit long enough to get them cold, but not so long to begin the freezing process.
  2. Image titled TakeOnionsOut Step 2
    Take the onions out of the freezer. Get a cutting board ready, as well as a sharp chef's knife. Do not use a serrated knife as it will shred the onions flesh and release to much juice.
  3. Image titled Slice Step 3
    Place one onion on the cutting board and slice it stem to stern. Do not peel your onion. Place the cut side on the board and slice off the root end and the top, about 12 inch (1.3 cm) from either end. Don't fret about lost onion, you want to create a good flat surface to begin cutting.
  4. Image titled Peel Step 4
    Pick up the onion and find a corner of the skin. It should peel off easily like a sticker. Try to peel it off in one large piece. You may also need to peel the first layer off due to discoloration.
  5. Image titled Hold Step 5 1
    Place the onion flat side down on the cutting board. Hold it in your the hand with your fingers curled under so that your fingernails are almost digging into the onion.
  6. Image titled SliceDown Step 6
    Place your knife against your knuckles. Without raising above your fingers slice down into the onion at the desired intervals. You may find the end of the onion slippery, just discard this part. Most injuries happen when trying to cut the last little bit, but don't bother, just cut another onion if you need more.


  • The flat side of the blade should rest lightly and slide up and down your knuckles as you slice. Keep your fingertips pointing away from the knife. It helps if you angle the knife slightly away from your hand so you can see the onion better.
  • Save any unused onion for the next time you make soup or stock. Onions freeze well when sealed.
  • Having sliced your onion, use quickly as the onion will start to make your eyes water as it warms up.


  • Don't touch your eyes while cutting the onion. This may cause them to burn. If this happens, rinse your eyes thoroughly.
  • Be sure to wash your hands thoroughly both before and after slicing your onion.

Things You'll Need

  • Knife
  • Cutting Board
  • Onions

Article Info

Categories: Food Cutting Techniques | Onions