How To Cut An Onion

Learn how to cut an onion in this post with step-by-step directions walking you through how to slice and dice an onion.

Adding onions to your cooking can add a lot of flavors and is a critical ingredient in many dishes adding rich umami flavor. Cutting them to a consistent size will help them to cook evenly.

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How to cut an onion instructions

In just a few simple steps I will show you how you can cut an onion two ways.

Whether you are dicing your onions to add to a sauce or maybe sauteeing strips for Fajita night you can follow along to learn how to cut.

You can use these techniques with many different kinds of onions such as red onions, Vadala onions, white onions, or even shallots. Any other onions alike can be cut using these steps.

Cut the stem end off

Using a sharp chef’s knife you will cut off the stem end of the onion which is the end with the dried stem that looks like a shoot. It is not the side that is grassy-looking.

Holding the onion steady on its side with the ends pointing outwardly, simply cut the stem end about 1/4 inch into the onion.

You are going to toss this part of the onion so the more you cut off, the less onion you will have left.

Make sure to leave the root end intact as this is going to help hold the onion together while slicing.

Cut the onion in half

Now that the stem end is cut off stand the onion on the cut end root side up. This will give you stability when cutting it in half.

Cut right through the middle of the root end, straight down through the onion. It is important to cut in the middle of the root end because this way both halves will be held together for the next step in cutting.

Peel the first layer of the onion

The skin of an onion is the top papery layer on the outside. Start by peeling the skin away from the cut end where the stem was.

Pull the skin back toward the root end removing it completely from the onion. If the skin is stubborn and won’t pull off the root ends you can simply pull it away enough so that it is out of the way.

For more in detail directions, you can go to my post on how to peel an onion with a video that shows you just what to do!

Cut the onion into slices

Lay half an onion flat on the cutting board holding it from the root end with your fingertips tucked back out of the way of the knife.

Cut across the onion from the stem end working your way back to the root end cutting strips as thick or as thin as you desire. That’s it! Sliced onions for salads, stirfry, or caramelized onions.

Cutting shallots is very similar, check out my post on how to cut shallots.

Dice the onion

Dicing onions a similar to slicing but with one more quick step. Lay half of the cut onion on the cutting board with the intact root end on one side.

Make cuts into the onion, cutting inward or lengthwise toward the stem end. Make sure to not cut through the root end.

You want to start down along the side making angled cuts through the onion as you work your way around to the other side.

You can make these cuts as close as you would like, noting that the closer they are together the smaller your dice with be.

Then you will cut across the onion like you would when making slices. Make sure to keep your fingertips back cut across your lengthwise cuts working your way toward the root end.

You will see the diced onion fall as you make each cut until you get to the root end at which you can now discard the root end.

There you have it! Diced onions are perfect for making sauces, and many other dishes that call for onions.

If you would like some tips on how to get that rancid onion smell off your hands when you are done cooking, check out my post on how to get onion smell off your hands!

How to cut an onion without crying

Cutting onions doesn’t have to be something to cry over. Although sometimes they will make you cry as soon as you make that first cut. The fresher the onion the less reaction you will have.

If you have ever wondered why onions make you tear when cutting them, it is because enzymes are released from the juices into the air when you slice through the cell of the onion.

These enzymes create a sulfurate acid which irritates the nerves around your eye causing them to burn. The tears are a natural reaction to protect your eye. So, no, you aren’t just a cry baby!

To avoid tearing up when cutting onions you can chill the onion before you cut into it by leaving it in the fridge for an hour or so.

Onions aren’t typically stored in the fridge but for this purpose, you could try them just before cutting them. If you want to learn more about how to properly store onions, check out my post.

Other ways to prevent crying when cutting onions are…

Anatomy of an onion

Knowing the difference between the root end and the stem end of the onion is important when cutting an onion. The stem end looks like a papery tip whereas the root end has dried roots or a grassy-looking knob.

The skin of an onion is the paper outer layer which will be removed when you start to cut into it.

How to cut an onion for onion rings

Cutting onions for onions rings can be a little tricky because onions are round so they want to roll around while you are cutting them.

Start with cutting the stem end off from the onion. Make a slight cut through only the skin layer of the onion. Do this by gently rocking the knife lengthwise from the stem end to the root end.

This will allow you to peel the skin off without cutting into the layers.

Hold the onion firmly on the cutting board with the root end toward your palm. Slice across the onion making slices about 1/4 -1/2 in thick. Continue to do this until you have reached the root end.

Now you have the sliced of onions and you can simply pull the ring out from each other and viola! Onion rings are ready to be dipped in batter, fried, and served with your favorite sauce!