Name: Onion Boil (Viral TikTok Recipe)
Prep time: 10 min
Cook time: 1 h 10 min
Total time: 1 h 15 min
Cuisine: American
Ingredients: 1 large (15 oz) sweet onion, peeled and ends trimmed off; 1 tablespoon vegan butter; 1 tablespoon extra-virgin olive oil; 1 teaspoon Cajun seasoning; ¼ teaspoon salt (plus more to taste when serving each layer); Optional: ¼ teaspoon garlic powder; Optional: ¼ teaspoon Old Bay seasoning; Optional garnish: finely diced parsley leaves

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Short Description

A tender, caramelized sweet onion roasted whole with butter, olive oil, and seasoning until each layer melts in your mouth—an effortless, flavor-packed side or snack that’s gone viral on TikTok.

Why You’ll Love This Recipe

Simple to prep: just one onion, a few pantry staples
Rich, sweet, and savory with minimal effort
Perfectly fork-tender as each ring separates gracefully
Customizable via seasoning tweaks and broiling for crispness

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
1 large (15 oz) sweet onion, peeled and ends trimmed off
1 tablespoon vegan butter
1 tablespoon extra-virgin olive oil
1 teaspoon Cajun seasoning
¼ teaspoon salt (plus more to taste when serving each layer)
Optional additional seasonings: ¼ teaspoon garlic powder, ¼ teaspoon Old Bay seasoning
Optional garnish: finely diced parsley leaves

Directions

Preheat your oven to 375 °F (190 °C).
Use a small melon baller or teaspoon to scoop out the top center of the onion about one-third of the way down, creating a shallow well.
Place the onion on a sheet of aluminum foil. Add the tablespoon of vegan butter into the well.
In a small bowl, whisk together the olive oil, Cajun seasoning, and salt (plus garlic powder and Old Bay if using). Pour this mixture over the butter in the well, allowing it to seep down the sides.
Season with any optional spices desired.
Wrap the onion tightly in the foil and set it in a small baking dish or cast iron skillet to catch any drips.
Roast in the center of the oven for 1 hour. After 60 minutes, open the foil to check: the onion should be fork-tender and slightly caramelized, with a jiggly center.
If it needs more time, re-seal and roast for an additional 10 minutes, then check again.
(Optional) To achieve a golden-brown top, turn the oven to broil, unwrap the foil, drizzle extra melted butter or olive oil, add a little more salt, and broil for 5–10 minutes, watching carefully to prevent burning.
To serve, peel away the outer layer and enjoy each inner layer with a sprinkle of salt if desired. Pour any collected juices from the foil over the onion. Garnish with chopped parsley if using.

Servings And Timing

Servings: 1 large onion yields 1–2 servings as a side or snack
Prep time: about 10 minutes
Cook time: roughly 1 hour (plus up to 10 minutes extra if needed), plus optional 5–10 minutes of broiling
Total time: around 1 hour 15 minutes

Variations

Use regular yellow onion or Vidalia onion instead of sweet onion
Try different seasonings: smoked paprika, chili flakes, or za’atar in place of Cajun seasoning
Replace vegan butter with dairy butter, ghee, or flavored compound butter
Add minced garlic or fresh herbs in the well for a boost
Serve with sides: roasted chickpeas, rice bowls, grains, or alongside grilled veggies
Make multiple small onions at once by using mini sweet onions and adjusting roasting time slightly

Storage/Reheating

Store any leftover roasted onion in an airtight container in the refrigerator for up to 3–4 days
To reheat, unwrap and place in a baking dish. Reheat at 350 °F (175 °C) for about 10–15 minutes, drizzle with a little oil or butter to maintain moisture
Alternatively, microwave slices gently for 30–60 seconds, covered, to warm through without drying out

FAQs

1. What Type Of Onion Is Best For This Recipe?

A large sweet onion (about 15 oz) like Vidalia or Walla Walla works beautifully thanks to its natural sugars, though yellow or white onions also work.

2. Can I Use Dairy Butter Instead Of Vegan Butter?

Absolutely—dairy butter or ghee can be used depending on your preference.

3. Is The Broiling Step Necessary?

No, broiling is optional. It enhances caramelization on top but the onion will be tender and flavorful without it.

4. How Do I Know When The Onion Is Fully Cooked?

It’s done when a fork slides easily through and the center jiggles slightly. If it’s still firm, reseal and roast for another 10 minutes.

5. Can I Prep This Ahead Of Time?

You can wrap the onion and refrigerate it overnight. Bring to room temperature before roasting; you may need to add a few extra minutes to the cook time.

6. What Can I Serve With Onion Boil?

It’s great alongside grains, rice bowls, roasted veggies, crispy chickpeas, or even as a flavorful side to grilled protein.

7. How Do I Adjust Seasoning Levels?

The recipe uses a teaspoon of Cajun seasoning and ¼ teaspoon salt. Feel free to reduce the seasoning or salt if you prefer milder flavors.

8. Can I Roast Multiple Onions At Once?

Yes—increase roasting time slightly and allow space between wrapped onions. Mini onions will cook faster than a large one.

9. Will The Onion Stay Moist After Roasting?

Yes—the foil seal traps juices. Make sure to pour these over the onion when serving or store them with the onion to retain moisture.

10. Can I Make This Recipe Without Aluminum Foil?

You can roast the onion uncovered in a baking dish, but you may lose juices and moisture. Covering with foil helps ensure tenderness.

Conclusion

Viral for a reason, the Onion Boil delivers deep, sweet, and savory flavor with minimal hands-on effort. This one-pot wonder turns a simple onion into a tender, caramelized delight that makes a memorable side or snack. Give it a try—and experiment with seasonings and broiling for your own signature version.