How to Grill Onions (And the Best Type to Use)

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Want to add onions to your grilling repertoire? Are you not quite sure where to begin?

In this TheGrillingDad.com guide, we’ll show you:

  • Which type of onions to use
  • How to grill them (without ruining them)
  • And much more!
how to grill onions

Grilling onions is an easy way to add flavor to your meals. You can use them in salads, as a side dish, and on sandwiches or burgers. They can be prepared cut or whole, take only a few minutes to prepare, and can be added to most meals.

Read on to find out the best ways to prepare perfectly grilled onions for your next outdoor get-together.

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Which Type of Onion is Best for Grilling?

There are so many types of onions at the supermarket:

  • Red
  • White
  • Yellow
  • Sweet
  • Shallots
  • Pearl 

When you go to choose the best onion to grill, you need to think about how you plan to prepare them and what flavors you want. 

The Best Grilling Onions

White Onions

Most commonly, people tend to grill white onions.

They have a sweet, mild flavor. They also contain less moisture than other onions. However, they are the worst onion for causing bad breath.

Red Onions

Red onions are great to pair with burgers, sweet potatoes, and squash. They have a stronger flavor that isn’t overpowered by the smokiness added during grilling. 

Still Really Good Grilling Onions

Yellow Onions

Yellow onions are less sweet and less pungent. They are great for adding a caramelized flavor to salads and sandwiches.

Spanish Onions

Spanish onions are another type of yellow onion, but they are slightly smaller and sweeter. These are used interchangeably with yellow onions. 

Sweet Onions

Sweet onions, as their name suggests, are sweet and best eaten raw, but they make great additions to grilling marinades and steaks.

Skewer Favorites

Pearl Onions

Pearl onions are small, sweet onions that are best used for kabobs.

Shallots

Grilled shallots are often used as garnishes and side-dishes and are also cooked with skewers.

white onions that have just been grilled

How do I Prepare the Onions Before Grilling?

The onion is a versatile ingredient. You can slice them lengthwise, grill them whole, chop them into wedges, or put them on a skewer. Each method allows for a difference in texture and usage. 

Slice Them, Dice Them 

The more common method is to slice the onion lengthwise.

You remove the skin and stem and make about ¼ inch slices, yielding approximately 4-6 slices per medium onion.

This method is usually directly applied to the grill, but sticking can become a problem, so a good cooking spray should coat the grates before you apply your onions.

This grilling method allows you to get a nice char on both sides of the onion. These are usually served on sandwiches and burgers

A Whole Lot of Flavor

Grilling onions whole is a great side dish for a steak or pork chop. These are usually made from sweet Vidalia onions.

The skin and core are removed, and then, the onions are covered in foil and stuffed with butter and seasonings.

They become melt-in-your-mouth smooth as the juices slowly roast.

Wedged 

Onion wedges are another great side dish,  garnish, salad-topping, or a nice pairing with wine and crusty bread.

The skins of wedges should be peeled. Leave the stem intact to prevent the wedges from falling apart during cooking. Slice the onion in half.

Then, in half again to make quarters. Finally, slice them one more time to create 8 pieces.

Wedges are painted with oil and applied to the grill. They should be rotated to get a nice char on all sides. 

Skewers

Of course, you can’t go wrong with a skewered onion.

You can slice, quarter, or place pearl onions on skewers whole.

Both wooden and metal skewers work well, although some cheaper wooden skewers can splinter, but these metal skewers by Blue Donut are reusable and affordable. If you love to grill using skewers, this would be a cheap yet durable investment.  

The benefit of putting your onions on skewers is your ability to control the cooking. You can turn the onions easier without them falling through the grates.

This also provides an easy method for getting onions off the grill without burning your hands in the process.

What Are the Seasonings for Grilled Onions?

The Spice of Life

Grilled onions have a great flavor just from the process of cooking, but there are some spices that you can coat your onions in to add more depth.

Simple salt and pepper can provide a lot of flavor to onions. Many people like to add paprika, chili powder, cumin, their favorite fresh herbs, or spice blends to grilled onions.

Play around with different spices and find a mixture that is good for you.

Oil it Up

No matter what method you choose, you are going to need oil to keep your onions from sticking to the grill.

You can go with a classic vegetable or spray oil, but you can also use ghee, butter, or olive oil to add more complexity to the flavor.

Butter or ghee is particularly good with steaks, pork chops, and chicken, whereas you may want to opt for a lighter oil such as olive or avocado oil for onions that will be a garnish or salad topping. 

Marinades and Sauces

The possibilities are truly endless. You can replace the oil with a marinade to add more flavor to the classic pungency of the onion.

Here is a list of sauces that pair well with grilled onions:

  • Honey mustard
  • Balsamic vinegar
  • BBQ Sauce
  • White Vinegar
  • Ginger-Honey salad dressing
  • Worcestershire sauce

There are many other marinades you could try. Get creative and try new flavors!

close up photo of a grilled sweet onion

How do I Prepare the Grill?

Which is Better: Gas or Charcoal? 

A charcoal grill is going to bring the smoky flavor from the coals, but it is harder to control the heat and may result in uneven cooking as well as sticking. Charcoal grills, however, are often cheaper.

With a gas grill, you can set the temperature and control how the heat is placed on the onions. This grill will give a more even cooking and be more reliable.

Either method, however, will result in delicious onions. 

Clean the Grill 

Before you begin grilling, make sure your grill is cleaned.

Onions can burn if they stick to the grates. Also, a dirty grill can be unsanitary.

To properly clean your grill in preparation for your onions, apply vegetable oil to the grates and use a spatula or paper towel to remove the grime.

This will not only get your grill clean, but also give it a non-stick coating. 

Be Equipped 

In order to grill onions, you will need:

  • A knife to slice the onions
  • A dish to put the onions on when they are done cooking
  • Tin foil and/or skewers
  • Vegetable oil
  • A spatula or tongs
  • And heat protective gloves

If you want to prevent sticking, you may also consider getting a cooking basket. This cooking basket by Grillaholics has holes that are punched from the inside out, which prevents food from getting stuck on the rough edges.

It is also nonstick, works on all types of grills, and is dishwasher safe. It is a great addition to your grilling tool kit

How To Grill Onions (5 Simple Steps)

Step 1: Preheat the Grill

Fire up your grill and let it preheat on medium if you have a gas grill.

If using charcoal, light the coals and allow the flames to die and the coals to turn an ash color.

Related >> How To Start a Charcoal Grill

Step 2: Peel and Cut the Onions

No matter what method you are using, you will want to remove the skin from the onions.

You can peel off the papery layer on top of the onion by grabbing it from the stem end and pulling gently.

Once you have removed the papery layer, you will want to cut your onion according to how you plan to prepare them.

This could be in slices, quarters, halves, wedges, or whole.

Step 3: Season the Onions

Next, you’ll want to put your seasonings on your onion.

You can go as simple as brushing the onions with vegetable oil and sprinkling them with salt and pepper.

However, you may want to try some of the other spices or marinades mentioned above. You would treat both methods the same way. 

You’ll want to coat the onion in about 2 Tablespoons of liquid per onion, and then sprinkle the seasonings on top of that.

You could alternately place the onion pieces in a zipper plastic bag, add the oil, add the spices, close the bag, and shake for easy application.

Step 4: Grill the Onions

Once your gas grill has heated, place your seasoned onions onto the grates.

You can also use a tin foil tent by taking a piece of tin foil, putting the onions on it, folding the long sides up, and rolling over the foil to create a tent.

If using skewers, place your onions on the skewers and then directly onto the grates.

Grill at 400 degrees Fahrenheit for 3-5 minutes on one side.

Flip our onions using tongs, and let them grill for another 3-5 minutes on the other side.

If using charcoal, you will want to move the coals to the sides of the grill and place the onions in the center of the grill grate to make sure that they don’t burn. 

Whole onions will take a slightly different cooking method.

For these, make sure to place the butter and herb-stuffed onions onto a cooking sheet and place them onto a medium heat grill at 300 degrees for 2 hours.

They should be falling apart and dripping in delicious, buttery juices. 

Step 5: Serve Them Up Right

After the onions have cooked on both sides, remove them from the grill using tongs and place them on the dish that was set aside.

You can separate the rings of slices for hamburgers, sandwiches, and salads; serve the wedges or whole onions alongside steak and potatoes; or put the skewers onto a platter for hands-on eating. 

Final Thoughts on Grilled Onions

Adding onions to your grilling routine is an easy way to pack flavor into your meals. There are so many different ways to grill onions that it would be hard to get bored with them.

This cheap and quick weeknight meal add-on, takes less than 10 minutes (for most methods) and really shows off your skills as a master griller. 

Sara P

Sara P

Sara is a mother of two who rediscovered her love of writing during the pandemic. She is a former teacher and current blog writer who enjoys cooking, crafting, gardening, and taking care of her family and pets.

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