Which Onions to Use When Cooking

Adding flavor to your favorite meals often includes adding garlic and onions. I don’t know about you, but I measure both with the heart, generally forgoing the measurement unit in many meals. To ensure that you make the best food possible though, you need to know which onion to use when you’re cooking. Better raw, ideal for grilling, special in stews, and correct for caramelization, the right onion is important to the overall result of your meal. This is how you can pick the perfect onion.


What Even are Onions?!

From the genus Allium – which includes shallots, garlic, and scallions – onions are one of the most widely cultivated vegetables. Yes, they are actually vegetables. Onions are nutrient-dense, low in calories, high in fiber and vitamin C, as well as calcium and iron. They’re great for your gut health too, the prebiotics feed your gut bacteria keeping your digestive tract healthy and happy. Their pungent wonderful scent is from the amount of sulphur present, which is why some are stronger than others. That being said, there are several different kinds of onions and their uses vary from dish to dish when cooking.


Yellow Onion (Spanish Onion)

The yellow onion is an all-purpose onion and the cornerstone of many different things, including mirepoix. Yellow onions are great for nearly everything and a good alternative if you are unsure about the onion to use in any recipe. Their flavor is sharp when yellow onions are raw but get mellow as they cook. These onions are full of starch and ideal for longer cooks like soup and stews, or under roasts because of this. It is best to cook a yellow onion because of their high sulphur content making them quite pungent.



Mirepoix is equal amounts of diced onion, carrot, and celery. This mixture is gently cooked with butter, or another form of fat, for extended periods without causing the Maillard reaction (browning) causing them to sweeten instead of caramelize. This is used in many soups, stews, and sauces.


White Onion

The crisp white onion is the onion to use when you want a sharp onion flavor that doesn’t linger too long when used raw like burger toppings, in salsa, potato salad, egg salad, and pasta salad. They are crisp and make a good substitution when you can’t get a yellow onion for cooking or red onion for raw applications. They’re very popular in Mexican cooking.



Sweet Onion

Sweet onions are fairly easy to get your hands on in North America. They’re also known as Mauis, Walla-Wallas, or Vidalia onions. They are fantastic raw with their less-intense and often sweeter flavor that still has a lot of onion-ness. These are the onions you want to use for caramelized onions and French onion soup. However, when caramelizing sweet onions, remember that they contain a lot of water that needs to be cooked off before the sugars can caramelize. Sweet onions are more delicate and tend to go mushy if cooked incorrectly, like too high heat for too long. Instead, use them in onion rings, for roasting - but not in a roast like yellow onions, sauté them too.



Red Onion

Cold and raw, these gorgeously colored onions are perfect for pickling and as toppings or in salad. Seriously you should try these quick pickled onions for your next burger or sandwich. They’re delightful on the grill too, gaining this sort-of jammy texture, smoky and roasted, instead of going mushy as some other onions will. Red onions range in color from the deepest purple to a stunning and bright magenta, to even a light-ish pink color on one side of the flesh, while remaining bright and white on the other. They have a mild and peppery flavor that gets sweet when they’re cooked. This flavor also becomes stronger with age, so the longer they remain unused, the stronger the onion-ness will be. These make an excellent substitution for white onions in dishes.




Shallots are the small, torpedo-shaped onions. They are mild and sweet, crisp and not pungent when compared to other onions. Some shallots can have a moderately garlicky flavor and even break off into cloves under the skin. Their skin – the papery stuff – can range from a red to golden brown hue. They’re ideal for any recipe and can be a substitute for any onion in any recipe when you don’t want too much of an onion flavor. When a recipe calls for shallots it would be calling for the whole thing unless otherwise specified. Shallots are the gourmet onion and used in restaurants to make anything with onions a little bit fancier. Shallots will add depth of flavor to caramelized onions, go great in vinaigrettes, and are amazing when sautéed with mushrooms and butter.


Cipollini Onion

An onion you don’t see that often is the cipollini. It is a smaller onion along the lines of a shallot, only they’re flat circles instead of torpedo-shaped. These onions are super mellow and become sweet and sort-of creamy when cooked adding an interesting depth of flavor and umami. Roast these onions like you would roast other veggies or use them to boost a roast of beef off the bottom of the pan. They’re sturdier than they look.



Green Onion & Scallion

Now for the toughie. Green onions. Technically they are not the same as scallions, however, the difference is minuscule, and they are relatively interchangeable. Green onion and scallions are of the same genus and species – Allium Fistulosum - but have a slightly different flavor. Scallions do not bulb, they are onions that are harvested while their shoots are still green. Green onions are harvested before the bulb part of the onion can grow. They have a stronger, more pungent onion flavor, especially in the white part. When working with both green onions and scallions cooking the white part is perfectly acceptable, while the green part is better suited to garnish and top things as it wouldn’t hold up to the heat. Green onions are most popular in Asian cuisine. Green onion and scallion are NOT the same as chives.



What is a Chive Then?

Chives are an herb that are part of the Allium family but with the classification of Schoenoprasum. They are a popular garnish and essential to French cuisine. They’re an aromatic grass with an edible lilac-colored flower. You can cook them but do so only briefly, because they will quickly lose their flavor. The flowers have a mild onion flavor compared to the stalk which is peppery and lightly-onion-y. Try garnishing your favorite meals with chives.



Tips for Working with Onions

The biggest thing about working with onions is the tears. It doesn’t seem to matter which onion, you always seem to tear up a little when it comes to slicing. This is because you are breaking the cells with your knife and dull ones are especially bad for this. Inside the cellular structure of an onion separate chemicals mix to form volatile amino acid sulfoxides. When an onion is cut, these chemicals form gases that mix with the water in your eyes to form sulfuric acid and stimulating your eyes to water making more sulfuric acid and even more tears.

  • Cutting Onions - Fewer Tears
    Chilling an onion before slicing will help prevent tears and so will using a very sharp knife as you won’t be damaging the cell walls as badly.

  • Storing Cut Onions
    Wrap cut onions tightly in plastic or a reusable wrap. They can live in the fridge for up to two weeks when stored in the vegetable crisper.

  • Storing Fresh Onions
    Fresh onions should be stored in a cool and dark place for about four to six weeks. Keep them in a paper or mesh bag so that they can have air circulation.

  • Purchasing Onions
    When buying individual onions, give them a squeeze and check on the outside paper. If there is damage to the paper down to the flesh, mold, or the onion is squishy, don’t buy it. For bagged onions, give them a smell. If they have a strong odor that is slightly sweet and earthy, there could be one or two bad ones in the bunch.

  • Serving Raw Onions
    Some onions are stronger than others and if you want to take that “bite” out of the onion you can do so by slicing them thin and soaking them in ice water while you are prepping other ingredients.

  • Cooking Onions and Garlic
    Onions take longer than garlic to cook. If a recipe calls for both to be sautéed or fried, cook the onion until it is nearly done and then add the garlic, ensuring the garlic won’t burn.

  • Caramelizing Onions
    One of the most delicious and easy to mess up things you can do with an onion is to caramelize it. This process needs to be done slowly over low heat. There is a lot of liquid that needs to evaporate before you can start to brown the sugars. This can take up to an hour depending on how many onions you have to caramelize. Don’t forget that they will also reduce in volume by quite a bit. What may seem like an insane amount at the beginning will seem minuscule by the end of things.




There are a surprising variety of onions out there and knowing which onions to use when you are cooking is very handy for making the best meals that you can. Other ingredients aside from your protein, when barbecuing, are just as important to the final product. Share your onion tips and tricks, favorite recipe featuring onions, or just your onion-tastic stories on our social pages like Facebook and Instagram, using the hashtags #Onions and #NapoleonGrills.

Happy Grilling!