Onion Boil

This viral onion boil recipe transforms onions into buttery, melt-in-your-mouth perfection. Easy, bold, and unbelievably good!

Course Side Dish

Cuisine American

Keyword onion recipes

Prep Time 10

Cook Time 1

Total Time 1 10

Servings servings

Calories 232kcal

Author Kathleen

Ingredients

4 large sweet onions, preferably Vidalia, about 8–10 ounces each
4 tablespoons unsalted butter, softened, divided
2 tablespoons olive oil, divided

Seasoning Blend

2 teaspoons Cajun seasoning
1 teaspoon Old Bay seasoning
1 teaspoon garlic powder
1 teaspoon paprika or smoked paprika, for deeper flavor
1/2 teaspoon kosher salt, adjust if your Cajun seasoning is salty
1/2 teaspoon freshly ground black pepper
1/2 teaspoon dried thyme, optional but recommended for depth

Finish

1 teaspoon fresh lemon juice, optional but highly recommended
fresh parsley, chopped

Instructions

Prep the oven: Preheat your oven to 400°F (204ºC).
Prep the onions: Peel the onions (4) and trim just enough off the root end so they sit flat, keeping the base intact.
Using a melon baller or paring knife, core out the top center of each onion about 1 inch deep, leaving at least ½ inch intact at the bottom so the onion holds together.
Score the tops: Lightly score the top of each onion in a crosshatch pattern, about 1 inch deep, to help the seasoning soak into the layers.
Make the seasoning paste: In a small bowl, mix 1 tablespoon of the olive oil with the Cajun seasoning (2 teaspoons), Old Bay (1 teaspoon), garlic powder (1 teaspoon), paprika (1 teaspoon), salt (1/2 teaspoon), black pepper (1/2 teaspoon), and thyme (1/2 teaspoon) until a thick, paste-like mixture forms.
Season and assemble: Place each onion on its own large piece of foil.
Drizzle the remaining 1 tablespoon olive oil over the onions, letting it run into the cuts and down the sides.
Push ½ tablespoon of butter into the center cavity of each onion (1 tablespoon total per onion), then spoon the seasoning paste into the center, letting it overflow down the sides.
Use any remaining seasoning paste to lightly coat the outside of each onion, then top each onion with another ½ tablespoon of butter.
Wrap for baking: Wrap each onion tightly in foil, sealing well so the butter and seasoning stay inside. Place them on a baking sheet for easier handling.
Bake: Bake for 45 minutes fully sealed.
Finish roasting: Carefully open the tops of the foil packets to expose the onions, then return them to the oven and bake for an additional 15 minutes, or until the tops are lightly browned and the onions are very tender.
Finish and serve: Transfer the onions to a serving dish. Spoon the buttery Cajun sauce from the foil over the top of each onion, then finish with a small squeeze of lemon juice (1 teaspoon) and a sprinkle of parsley.
Serve immediately.

Notes

Don’t skip scoring the onion. Those small cuts help the butter and seasoning soak into every layer instead of just sitting on top.
Use heavy-duty foil. If the packet leaks, you lose both moisture and flavor. Double-wrap if needed.
Opening the foil at the end allows the onions to caramelize slightly while the butter reduces into a rich, concentrated sauce.
Balance the richness. A small squeeze of lemon at the end makes a huge difference — it cuts through the butter and makes everything pop.
Adjust the spice level. Cajun seasoning blends vary quite a bit in salt and heat, so taste and adjust to your preference.

Nutrition