What is the Best Kind of Onion to Use for Fajitas?

by Charlie
Onion to Use for Fajitas

If you are a big fan of fajitas, you might be wondering what the best ingredients to use in them are – and in particular, which onions are the best for this delicious meal. Traditional fajitas are a dish well worth putting the time and effort into, so let’s understand a bit more about what they involve and which onions to use.

Onions have to be one of the most important elements of fajitas, and they can subtly but totally alter the flavor. That’s why it really matters what onions you put in there. They may not be the dominant flavor, but they will make a big difference to the overall taste.

What is the best kind of onion to use for fajitas? Traditional fajitas use white onions, although you can choose yellow or red if you prefer those flavors. However, white onions tend to have a more robust flavor and lend the dish more of their essence, while yellow and red onions are often mellower and will be very subtle in the fajita.

Why Do We Use White Onions for Fajitas?

White onions are often used in Mexican cooking because they are flavorful and crisp, and this suits the other flavor combinations well. White onions lend a bit of a “kick” to the fajitas (and other Mexican dishes), making them powerful and delicious culinary experiences.

Because the onions are only cooked for a short period of time, white onions are particularly noticeable. As the fajita contains many other flavors too, this is necessary if you want to notice them, and they may otherwise be drowned out by the other ingredients.

If you enjoy onions and the spicy bite they provide, white onions are the best option for fajitas, but if you find white onions challenging and too hot, let’s look at some other options.

Can You Use Red or Yellow Onions for Fajitas?

Yes, you can use red or yellow onions for fajitas if you would prefer. Many recipes call for these instead, diverting from the traditional white onions to provide different flavor combinations and less hot options for those who do not enjoy heat but do like fajitas.

In general, you’ll probably find that yellow onions are pretty similar to white ones. They may not have quite such a strong flavor, but they are not far off, so they make a great substitute if you wanted white onions but couldn’t source them.

Red onions, on the other hand, have a slightly sweeter flavor, and don’t provide the same burn as white onions. They aren’t common in Mexican cooking because they are not so powerful, but they work just as well. A good handful of red onion can still give the fajita a nice heat and add to its flavor.

If you’re struggling with the white onion, consider swapping some or all of it to reduce the heat. You can incorporate a little bit of red/yellow onion, and dial the fajita’s “kick” up or down as you prefer. Reducing the amount of onion in the dish is a great way to make fajitas a little more child-friendly, especially if you have a picky eater to feed.

If you plan to use raw onions in your fajitas instead of cooked ones, the mellower flavors are likely to be better. Although some people enjoy raw white onion, many others find that it’s too strong for them and they can’t cope with it.

How Do You Cut Up Onions For Fajitas?

Regardless of what kind of onion you’re using, you want to try and get the slices as even as possible. This will ensure the onion cooks nicely. It reduces the chance of over-cooking and makes it easier to spread the onion through the fajita, rather than ending up with big lumps of onion in certain areas.

Even cooking is important to maintaining the onions’ texture and flavor. If your onion is all in different sizes, it won’t sauté properly, and you’ll find that parts of your fajita don’t taste quite right, because the onions are improperly cooked.

To get similarly sized pieces, you are going to start by removing the onion’s top and tail. Once both ends have been trimmed off, place your onion with one of these new flat surfaces down to give yourself a stable vegetable to cut up. Remember to be careful not to cut yourself as you work.

Cut the onion in half, and remove the skin from both halves. Next, put one of the halves with the cut side down and one of the cut ends facing toward you (it does not matter which).

Begin to slice, from the top to the bottom of the onion, so your knife both starts and finishes at the stems you cut off. Work slowly so that your slices end up approximately the same thickness. Your end slices will usually end up being a little bigger, so you can then trim these down to size.

Next, do the same for the other half of the onion, and gently separate out the layers. You will now have some pieces of onion that are all similar sizes; these will cook much more evenly than if you cut your onion into rings. They will sauté beautifully, and leave you with delicious onion pieces in your fajita.

If you would rather have bigger pieces, you can instead face the stem ends away from you, and cut across the onion to get large semi circles of onion. These may need to be sautéed for a little longer, as they will be larger, but this is another good option for fajitas.

Final Thoughts

On the whole, a fajita is most commonly made with evenly sliced and gently sautéed white onion. This is the best way to capture the traditional flavor and kick that real Mexican fajitas offer, and many people enjoy them like this.

However, if you struggle with the strength of the onion or you don’t have white onions to hand, yellow and red onions make a reasonable substitute. Red onions will not give the food as much bite as yellow or white onions, but they will still work, and they are preferred by many people.

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