Onion Boil

Name: Onion Boil
Prep time: 5 min
Cook time: 55 min
Total time: 60 min
Ingredients: 4 medium sweet onions (washed, peeled, and ends trimmed off); 4 tablespoons butter (or oil); 4 ounces Gruyere or Swiss cheese (about 1.5 inches each); 2 tablespoons extra virgin olive oil; 1 tablespoon cajun seasoning; 1 tablespoon smoked paprika; 1 teaspoon kosher salt; 4 garlic cloves (peeled); finely chopped parsley (Optional)

By Rena Awada, nutritionally reviewed by Ella Davar RD

5 from 1 vote

Dec 26, 2024

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Making Onion Boil is quite simple, and it’s so tasty—especially if you love onions. Tender, juicy, and flavorful, it makes for a simple appetizer or side dish and only needs pantry staples.

Baked onion boil with seasoned melted butter on a round white plate.

When life gives you onions, make onion boil. If you’ve been on TikTok you must have come across videos of the viral onion boil in which onions are actually baked and not really boiled. It’s super easy to make too. You core the onions, add butter in the middle, then sprinkle any of your favorite seasonings to it. Wrap the whole thing with aluminum foil and bake for a good 45-55 minutes depending on the size of the onions. The cool thing about the tiktok viral onion boil is there isn’t a specific seasoning you MUST use. Everyone makes it with what they have on hand.

I liked adding cheese to this one because I wanted it to have that hint of French onion soup to it. A lot of times I like serving this with a couple of boiled eggs, or a side protein.

Ingredients needed

Below is a list of ingredients you will need to make this onion boil recipe. Full measurements are listed further down below in the recipe card.

Sweet onions, washed, peeled and ends trimmed off
Butter
Cheese: Gruyere or Swiss cheese, optional
Extra virgin olive oil
Seasonings: cajun seasoning, smoked paprika, and kosher salt
Garlic cloves- use fresh garlic
Optional: finely chopped parsley to garnish

How to make onion boil

Preheat the oven to 375 F.

Step 1: To prepare the onions, wash, peel, cut both ends off, and discard. Using a melon baller, scoop out some of the inside of the onions to create a space for the fillings in the center. In a small bowl, combine the oil and seasonings.

cheese and butter being added to the cored onions.

Step 2: Stuff each onion with a cube of butter and a cube of cheese.

Seasoned oil is drizzled over the onion.

Step 3: Cut four squares of aluminum foil and place the onions in the middle of each. Drizzle with the seasoned oil and top with the garlic cloves.

4 covered onions with foil in a baking dish.

Step 4: Wrap the aluminum foil all over the onions and place them in a baking dish. Bake for 45-55 minutes, or until fork tender. Serve with cooked rice or roast.

Baked onion with seasonings and butter in a foil wrap, opened, on a cutting board.

How to make in an air fryer

If you prefer to make this recipe using your air fryer instead of the oven, simply follow these steps.

Preheat your air fryer to 350°F (175°C)
Once you have cored the onions, add the butter and seasonings, and wrap each one in a foil wrap.
Place wrapped onions in the bottom of the air fryer basket. Air fry for 45 to 60 minutes or until the onion is soft and cooked through.
To check if it’s done, pierce the onion with a fork or skewer. If the onions are fully cooked, the fork should slide in easily.
Remove from the air fryer and set the onions on a plate. Drizzle the juices on the foil over the onions and serve.

Recipe Notes

The size of the onions won’t matter. If you choose to use large onions, they will need more time to get really tender.
The cheese is optional, but I liked adding it in. Any soft and melty cheese will work like fontina, havarti, gruyere, and provolone.
You can use any other seasonings of your choice.
Handle it with care when you remove it from the oven. It will be very hot. Let it sit for a few minutes to cool off before eating.

baked onion on a plate cut in the middle with fork on the plate.

Frequently asked questions

How to store onion boil?

If you have leftovers, place them in a sealed container and store them in the fridge for up to 4 days.

Can I freeze onion boil?

Yes. If you want to cook them ahead to freeze them for later use, you can. Follow the same directions until the onions and cooked. Remove from oven and let it cool completely before placing them in a freezer safe container or bag and freeze for up to 3 months.

How to reheat onion boil?

If the onion boil is still in the foil packet, reheat them in the oven. Preheat the oven to 350 F and reheat them for 15-20 minutes or until it’s heated through. Ovens vary. If the onion boil is unwrapped already, you may reheat in the microwave for 30-40 seconds or until its heated through.

Can I only use oil instead of butter?

Yes. If you want to just use oil, you can swap the butter with avocado oil instead.

Can I make THE onion Boil ahead?

Yes. This is a great make-ahead recipe. You can follow the same steps up until its time to put it in the oven. Instead, place them in the fridge until you are ready to make them the next day or two.