This simple tutorial for how to cut an onion is a game-changer for any home cook. Chopped and sliced onions are such a common ingredient in all kinds of recipes as onions are a crucial flavor-builder. So, knowing different ways to cut onions is super important! Thankfully, it’s a very easy skill to master.
In this post, I’ll share step-by-step instructions for the best way to slice and dice onions, the difference between different types of cut onions, and a few tips to cut an onion without crying! For more easy kitchen hacks, see my posts for how to soften butter, how to make brown sugar, and how to toast pecans.
Choosing The Best Onions
Look for an onion that is firm all the way round and even in color. The onion skin should be dry and papery and have no blemishes. Surface dirt is okay, as it can simply be rinsed off. Whole onions should be stored in a cool, dry place.
Onions that are improperly stored can develop a black or green mold between the skin and the top layers, but you can typically see it through the papery skin. Avoid any onion that has soft spots or any spots that appear dark or wet.
This is the same for all types of mature onions (with papery skins), like red onions, yellow onions, white onions, sweet onions, and shallots.
What’s The Difference Between Chopped, Sliced, And Diced Onions?
Chopping an onion refers to cutting it into chunks that are not necessarily regular in shape. Diced onions are a type of chopped onion, but they are cut into smaller, more uniform onion pieces. A sliced onion is cut into long, thin pieces.
How To Cut An Onion
1. Use a sharp knife to cut the onion in half through the root end and the pointed tip. Place the cut sides on the cutting board and slice off the pointed tip (stem end). Do not cut off the root end!
2. Peel off the onion skin. Set one-half of the onion aside. Place the other half, cut side down, on the cutting board. Ensure the root end of the onion is not facing your body but is rather facing the right or left.
3. How to slice an onion: Hold the onion half in place with your fingers, then tuck your thumb behind the fingers for safety and stability. Start at the cut end of the onion (not the root end). Place the blade of your knife on top of the onion (parallel to the root end) and slice through the onion completely, down to the cutting board. Make thin or thick slices, depending on what you need. When you have finished the final cut, discard the root end. Repeat with the other half of the onion.
4. How to dice an onion: Place your hand flat on top of the onion half, pressing it into the board. Turn your knife so that the blade is facing the cut end. Start down near the cutting board and make a cut almost all of the way through the onion, stopping about ½-inch before the root end. Repeat to make 2 to 3 more horizontal cuts, ½-inch above the prior cut. You can make the cuts closer together or father apart for a small dice, medium dice ,or large dice.
5. Keep the onion on the board and turn the knife so that the tip faces the root end and the blade is on top of the onion. Starting at the side of the onion nearest your body, cut through the onion, from the top all of the way through to the cutting board. Repeat these cuts every ½-inch.
6. Finally, turn your knife perpendicular to the onion (parallel to the root end). Hold the onion half in place with your fingers, then tuck your thumb behind the fingers for safety. Start at the cut end of the onion (not the root end). Place the blade of your knife on top of the onion and slice through the onion completely. Small cubes of onion will form on your board.
How Do I Cut An Onion Without Crying?
Onions contain compounds that release and combine when cut, producing a gas called “syn-propanethial-S-oxide.” It isn’t harmful, but it can make your eyes tear up! Here are a few tips for how to cut an onion without crying:
- Leave the root intact: This prevents irritating compounds from being released and exposed, which will reduce the risk of any eye irritation.
- Chill the onion: While you don’t want to store onions in the fridge, you can place one in the fridge for 30 minutes or freezer for about 15 minutes before cutting it. The cold temperature makes the gas less volatile and, therefore, less likely to make you tear up.
- Wear goggles: It may feel a bit silly, but wearing onion goggles or swimming goggles is one of the most effective ways to protect your eyes while cutting onions.
- Turn on your kitchen vent: The fan can help pull the fumes away from you, protecting your eyes. Cutting the onion near an open window can also help.
I also recommend washing your hands immediately after cutting the onion and wiping down your knife and cutting board as well.
Ways To Use Cut Onions
Sliced: Sliced onions are great in salads, as a sandwich or burger topping, to make caramelized onions, or when a recipe calls for larger pieces of onions, like for:
Chopped or Diced: Diced onions are the most common type in recipes because they are so versatile. Use them in soups and stews, chunky sauces, salads, and as a filling for casseroles:
Finely Chopped (minced): Minced onion is perfect when you want the onion to be well incorporated or to not have large chunks of onion in whatever you are making. Finely chopped onion is great for meat mixtures, smoother sauces, salad dressings, and dips:
- Turkey meatballs
- Chicken burger
- Guacamole
- Pineapple salsa
- Vinaigrettes or sauces
How to Store Chopped Onions
Chopped onions will keep in the refrigerator for about 7 days in an airtight container or zip-top bag.
Pro Tips For Making This Recipe
- Clean the onion first, if needed. If the onion has dirt on the outside or in the root end, rinse it off and dry the onion before cutting it.
- Use a sharp knife. Using a very sharp knife makes cutting an onion safer and more effective. A dull knife can slip, increasing the chances of a cut.
- To prevent the cutting board from slipping, place a damp kitchen towel or damp paper towel under the cutting board to keep it in place.
Frequently Asked Questions
No! Whole onions will keep very well in a cool, dry place (like a pantry) for about a month. Once chopped, onions need to be refrigerated. Other varieties of fresh onions, like scallions, green onions, or spring onions, do have to be refrigerated and are very different from mature, papery onions.
Yes, you can freeze chopped onions for up to 6 months. Store them in a freezer bag or freezer-safe container. You can thaw them first or cook with them straight from frozen.
This method for how to cut an onion will work for white, yellow, sweet, and red onions, as well as large shallots. A different method is needed to cut green onions and small spring onions.
Check out my recipe for air fryer onion rings to learn how to cut onion rings quickly and easily.
If you love this recipe try these out!
If you’ve tried this how to cut an onion recipe, then don’t forget to rate it and let me know how you got on in the comments below. I love hearing from you!
How To Cut An Onion
Equipment
- Knife
- Cutting board
Ingredients
- 1 onion
Instructions
- With a sharp knife, cut the onion in half through the root end and the pointed tip.
- Place the cut sides on the cutting board and slice off the pointed tip. (Do not cut off the root end. Leave it intact.)
- Peel the skin away from the onion.
- Working with 1 half of the onion at a time, place the cut side on the cutting board. Arrange the onion so that the root end is facing to either the left or right side of you (not facing your body).
How to Slice an Onion:
- Hold the onion half in place with four fingers, then tuck your thumb behind the fingers. Start at the cut end of the onion (not the root end). Place the blade of your knife on top of the onion (parallel to the root end) and slice through completely, down to the cutting board. Move your fingers back toward the root end as you slice the entire half, making the slices as thick as you like. When you have finished the final cut, discard the root end.
How to Dice an Onion:
- Place your hand flat on top of the onion half, pressing it into the board. Turn your knife so that the tip of blade is facing the cut flat end. Start down near the cutting board (about ½-inch from the bottom side of the onion) and make a cut into the onion, almost all of the way through it, stopping about ½-inch before the root end. Remove your knife and repeat, to make 2 to 3 more cuts, ½-inch above the prior cut. You can make the cuts closer together for a small dice or father apart for a medium dice or large chop.
- Next, keep the onion on the board and turn the knife so that the tip faces the root end and the blade is on top of the onion. Starting at the side of the onion nearest your body, cut through the onion, from the top all of the way through to the cutting board. Repeat these cuts every ½-inch, moving across the whole onion half away from your body.
- Finally, turn your knife perpendicular to the onion (parallel to the root end). Hold the onion half in place with four fingers, then tuck your thumb behind the fingers. Start at the cut end of the onion (not the root end). Place the blade of your knife on top of the onion and slice through completely, down to the cutting board. Move your fingers back toward the root end as you cut the entire onion half. Small cubes of onion will form on your board.
Notes
- Clean the onion first, if needed. If the onion has dirt on the outside or in the root end, rinse it off and dry the onion before cutting it.
- Use a sharp knife. Using a very sharp knife makes cutting an onion safer and more effective. A dull knife can slip, increasing the chances of a cut.
- To prevent the cutting board from slipping, place a damp kitchen towel or damp paper towel under the cutting board to keep it in place.
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