3 ways to cut an onion easily, safely, and without crying

• Common ways to cut up an onion include dicing, mincing, and slicing.
• A sharp chef's knife is the best tool for cutting onions and will minimize eye irritation.
• Chopped onions can be stored in the fridge for up to a week or the freezer for up to three months.

Countless savory recipes begin with onion, whether it's sliced, diced, or minced. "[Onions] are the flavor backbone of so many savory dishes," says Kyrsten Beidelman, regional manager of Hipcooks, a company that offers hands-on cooking classes.

No matter what your recipe calls for, it's important to learn the basics of cutting an onion. "In general when cooking, you want things to be cut in a similar size and shape so they cook evenly, look nicer, and have a better 'mouthfeel' when you're eating them," says Beidelman. With a little know-how, you're less likely to injure yourself and your meals will have better flavor and texture.

To minimize accidents, follow some basic safety precautions when slicing and dicing. In addition to using a sharp knife, Beidelman recommends keeping your cutting board clean and uncluttered, moving anything you're not actively cutting to a prep bowl. Before chopping, check your finger positions. When holding the onion, your fingers should be curled under to keep any fingertips away from your knife.

When shopping, Beidelman recommends looking for onions that have their skin intact and are firm with no soft spots. The following methods for cutting onions apply to all types of bulb onions, including red, white, sweet, and yellow as well as shallots.

Quick tip: When onions are cut, they release syn-propanethial-S-oxide, an irritant that causes eyes to burn and water. To reduce irritation, Beidelman recommends using a very sharp knife, since, "it will more cleanly cut through the onion, break open less cells within the onion, and cause less fumes to release that make us cry."

How to slice an onion

When a recipe calls for sliced onions — little half moon slivers — it means they will play a noticeable part in the dish since the strands will be discernable in the finished dish. "Sliced onions are great in a stir fry, stew, tacos, on top of a pizza, or caramelized for an intense and sweet golden brown and turn them into onion soup or a dip," says Beidelman.

When slicing, dicing, or mincing, use a sharp knife. A chef's knife is best, since it is large enough to slice through a whole onion in one motion.

1. Trim the ends. Place a clean onion on a cutting board with the top and bottom facing left and right. Using a sharp knife, slice off about ½ an inch of the pointy stem end and barely slice off the brown root end, just removing the roots.
2. Cut in half. Sit the onion up on the cut stem end. Slice right down the middle, cutting it into two equal pieces.
3. Peel. Remove the peel from both sections of onion. Place one half cut-side down in the center of the cutting board with the stem end pointed towards your dominant side (for most people, right) and move the other half of the onion to the side.
4. Slice. Hold the onion in place with your non-dominant hand. Slice the onion, starting at the stem end, in a rocking motion towards you from the tip of the knife to the base, creating crescent slices. Space your cuts depending on how thick or thin you want your slices. Keep your fingertips curled in and adjust your grip as you move down the onion to avoid nicking your fingers or knuckles.

Quick tip: To make onion wedges, turn half of a peeled and trimmed onion so that it sits flat on the cutting board with the trimmed stem end pointing towards you (instead of left to right). Slice the onion at an angle, mimicking the slices in an orange, to make wedges.

How to dice or mince an onion

A common method for preparing onion is dicing. Onion is chopped into small, square-shaped pieces so that the dish is better infused with its flavor, whether left raw in a salsa or salad dressing, or cooked in a soup or sauté. "Think of [diced onion] as your flavor base, then start laying more flavors from there," says Beidelman.

1. Trim the ends. Use a sharp knife to slice off about ½ an inch of the stem end and lightly trim the root end.
2. Cut in half. Sit the onion up on the cut stem end. Slice into two equal pieces.
3. Peel. Remove the peel from both sections of onion. Place one cut-side down in the center of the cutting board with the stem end facing towards you.
4. Slice. Cut through the onion vertically from end to end every half inch, stopping short about ½ an inch from the root end. This will result in a standard, medium dice. As you cut, angle the blade slightly inward towards the center of the onion. The onion should be cut into strips but still in one piece, held together by the stem end.
5. Dice. Turn the onion 90 degrees with the stem end pointed towards your dominant side. Hold the onion steady as you slice through it vertically every half inch starting at the trimmed stem end. You will be cutting across the horizontal cuts you just made, yielding small squares of onion.

Quick tip: For a large dice, make your cuts ¾ inch apart and for a small dice, make your cuts every ¼ inch. For minced onion, Beidelman recommends starting with a pile of medium diced onion and rocking your knife through the pile until the pieces are very small.

How to slice an onion into rings

Thick-sliced onion rings are commonly used to make battered and fried onion rings, while thin rings can be added to salads or used to top casseroles. While it's a simple cut, use caution. The onion is left whole before slicing to achieve perfect circles, making it more likely to roll around your cutting board.

1. Trim one end. Trim about ½ an inch from the pointy stem end.
2. Peel. Carefully peel off the skin. If the skin is tough to remove, Beidelman recommends running the tip of your knife down the onion from top to bottom, just barely piercing the top layer, and peeling away the layers of skin.
3. Slice. Place the peeled onion on the cutting board with the trimmed stem end facing your dominant side. Use your non-dominant hand to steady the onion on the board as you slice down to cut the onion into rings. Adjust the width according to how thick or thin you want your onion rings.

How to store cut onions

Chopped onions can be stored for a future meal, cutting down on prep time. Store chopped or sliced onions in an airtight container or zip-top bag in the refrigerator for five to seven days. They can sit at room temperature for up to an hour, then they should be cooked or moved to the fridge. If you have half an onion leftover, it will keep in an airtight container for a few days or, wrapped tightly in plastic wrap, about a week.

You can also freeze diced or sliced onions in an airtight container for up to three months. Beidelman points out that freezing does affect the texture since water inside the onions turns to ice and then separates out once they thaw, making them limp. Frozen, thawed onions are best used for cooked applications. "They're great for use in soups, stews, casseroles or in something that will be blended," she says.

Insider's takeaway

Using the proper technique to cut onions will yield better finished dishes. Slice off the stem end and lightly trim the root end before peeling and either slicing, dicing, or cutting into rings. Using a sharp chef's knife will decrease your risk of injury and minimize any eye irritation. Store any leftover chopped onion in the fridge for up to a week.

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