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Onion Boil Recipe

Michelle
Whole sweet onions baked or grilled in foil with garlic butter and seasonings until tender, then topped with parsley and crispy bacon.
Print Recipe
Prep Time 10 minutes
Cook Time 1 hour
Total Time 1 hour 10 minutes
Course Side Dish
Servings 4

Equipment

  • Cutting board
  • Sharp knife
  • Spoon (for filling onions and basting)
  • Measuring spoons
  • Small mixing bowl
  • Tongs (for handling hot onions/packets)
  • Baking sheet (oven method with foil)
  • Heavy-duty aluminum foil (foil packet method)
  • Dutch oven with lid (best no-foil method)
  • Deep baking dish with a tight-fitting lid (or covered casserole dish)
  • Air fryer-safe ramekins or mini baking dish (no-foil air fryer method)
  • Skillet (or air fryer) for crisping bacon

Ingredients
  

  • 4 large sweet onions Vidalia or sweet yellow
  • 6 tablespoons unsalted butter softened
  • 4 cloves garlic minced
  • 2 tablespoons olive oil optional
  • 1 teaspoon paprika
  • 1 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 2 teaspoons Worcestershire sauce optional
  • 1 tablespoon brown sugar optional
  • 2 tablespoons chopped fresh parsley
  • 6 slices bacon cooked until crisp and chopped (garnish)
  • Lemon wedges for serving (optional)
  • Optional moisture boost: 2 teaspoons broth per onion only if you want a little extra steam inside the foil

Instructions
 

  • Preheat: Oven: 400°F (205°C)
  • Grill: Medium heat (aim for 375–425°F), preferably indirect heat
  • Cook the bacon (for topping): Cook bacon until crisp, then chop. Set aside (this keeps it crunchy for garnish).
  • Prep the onions: Peel onions and trim just the root end so they sit flat (don’t remove the root completely).
  • Core the center: Cut a deep cone-shaped hole in the top center of each onion (about 1–1.5 inches wide). Keep the onion whole and intact.
  • Make the garlic butter: In a small bowl, mix softened butter, garlic, paprika, salt, pepper, and (if using) Worcestershire and brown sugar. Add olive oil if you want it extra silky.
  • Foil wrap: Place each onion in the center of a large sheet of heavy-duty foil (or double-layer regular foil).
  • Fill the onion: Spoon a generous amount of garlic butter into the center hole and smear a little over the top.
  • Optional broth tip (tiny amount): If you want extra steam insurance, add 2 teaspoons broth into the foil packet near the base of the onion (not pouring over the top). Totally optional.
  • Seal tightly: Wrap into a snug packet, leaving just a little space above the onion for steam.
  • Cook until tender: Oven: 45–60 minutes on a baking sheet or Grill: 45–60 minutes, turning once halfway
  • The onion is done when a knife slides in easily.
  • Finish: Carefully open the foil (watch the steam). Sprinkle with parsley and a handful of crispy bacon pieces. Add lemon squeeze if you like, and spoon the buttery juices over the onion.

Notes

  • No broth is needed onions release their own moisture.
  • If you want extra steam, add 2 teaspoons broth per onion inside the foil packet.
  • Add bacon only after cooking so it stays crisp.
  • Cook time depends on onion size; bake/grill until a knife slides in easily.
Keyword Onion Boil Recipe