How to thinly slice an onion


We can't promise you won't cry when you slice onions, but we can promise that you'll enjoy watching Marc Bauer, Master Chef at the renowned French Culinary Institute and its popular L'Ecole Restaurant show you how to thinly slice an onion.

How to thinly slice an onion
  1. Using a paring knife, cut part way through the root of the onion.
  2. Pull the skin away from the onion using the paring knife's blade and your finger.
  3. If there is a second woody skin-like layer, remove it.
  4. Place the onion on your cutting surface with the root end of the onion to your left.
  5. Using your right hand, hold the blade of your chef's knife between your thumb and index finger, and wrap your other three fingers around the knife's bolster. (The thick junction between the handle and the knife blade.)
  6. Curl your fingers of your left hand into your palm and hold the onion so that you can rub the knife blade against your knuckles of your index or middle fingers while slicing the onion. (Use this technique for all slicing. It's a safe way to prevent you from inadvertently cutting the tips of your fingers!)
  7. The key cutting technique is to slide the blade across the cutting board and through the onion so that you slice the onion rather that crushing down on it while cutting. Place the point of your knife just in front of the onion and move your knife forward and down through the onion. (Note: By cutting rather than crushing the onion, you do less damage to the onion's cell structure, and reduce the enzymes that are released. This is what causes eye irritation. Never touch your eyes after handling onions, and try to cut them in a well-ventilated space. You can also wear goggles.)
  8. When you have completed slicing most of the onion, turn the remaining piece down flat on the cutting board and continue slicing. Use the root for soup or a stock.
Transcript Hi I'm Marc Bauer. I’m from the French Culinary Institute. I’m going to peel and slice an onion. So I will use a paring knife. Start first with the root. I don’t want to cut all the way through the root just part of it, and pull that skin off. Many people say, ‘oh an onion makes me cry,’ but if you open a window in your kitchen it will alleviate the noxious gas that hurts your eyes. You can also, some people wear goggles, but I don’t do it in public. But, you can also do it under a hood, an exhaust hood. So you see you pull with your finger and your blade that first skin. Now if you notice that layer that’s a little woody just remove that next layer. No matter what never touch your eyes when you cut or peel an onion.

So once it’s peeled I will use my chef knife. You hold with the three fingers you hold this part, the bolster, and hold my thumb on one side, my index on the other. That’s how I hold my chef’s knife. Now what I want to achieve is sliding the knife on the board that way. So it slices through the onion, it doesn’t crush through the onion. Uh, we said slice, so I will put the point of the knife down. The root of the onion is on my left, and go forward and slice. Forward and slice. The idea is that the point of the knife goes right above the onions—the onion, and go forward not by crushing through the onion, but slicing by going forward and down. Now once you get used to slicing you can use the index finger or the middle finger and guide the knife by using the first knuckle as a guide. In the long term it’ll be much more helpful to the speed in which you can slice something if you still have them. So—[laughs] don’t laugh, no worries. So, once you get used to use those knuckles, you really, is much faster and safer.

Once I get to the end of the onion, I push the flat side down and continue slicing like this. Again. So I look for stability in the onion. That’s it. The little ends you can put in the soup, in the stock. That’s it: sliced onions. Thinly sliced onions.  
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  • Marc Bauer

    Marc Bauer Master Chef, French Culinary Institute Marc Bauer is a Master Chef and Roundsman at the renowned French Culinary Institute and its popular L'Ecole Restaurant in New York City. more about this expert »

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