A whole sweet onion bakes in a foil packet with spiced butter until its layers turn silky and spoon-tender. Pour the buttery juices over every bite.
Despite the name, an Onion Boil cooks in the oven: a snug foil packet traps the onion's own moisture around the seasoned butter. The outer layers soften slowly while the center keeps its shape, giving you broad petals to pull apart with a fork.
Pick onions of similar size so they finish together. Cut a small well in the top for the butter, leaving the base intact to hold the juices inside the packet.
Method
Heat the oven to 375°F (190°C). Trim just enough from each onion base for it to stand. Cut a narrow well into the top, stopping well above the root, and score a shallow cross across the top.
Mix the butter with paprika, garlic powder, thyme, salt, black pepper and cayenne. Set each onion on a large square of foil and divide the butter between the wells and tops.
Seal the foil into tight packets and place on a sheet pan. Bake for , until a thin knife slides easily through the center; larger onions may need another .
Open the packets carefully, spoon the collected juices over the onions and scatter with parsley. Serve in shallow bowls to catch the butter.
Forkue tips
- A deep cut through the base releases the butter before the center softens; keep the bottom of the onion whole.
Storing and reheating
Refrigerate the onions with their buttery juices for 3 days. Warm covered in a 350°F oven until hot, or slice and gently reheat in a skillet with the juices.
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Kitchen gear
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Onion Boil: FAQ
Why is the middle of my onion still firm?
The packet may be loose or the onion unusually large. Reseal it tightly and continue baking until a knife reaches the center without resistance.
What do I serve with a baked onion?
Serve it beside roast chicken, grilled steak or beans and rice. The spiced butter in the packet also works as a sauce for potatoes.
How do I store and reheat Onion Boil?
Refrigerate the onions with their buttery juices for 3 days. Warm covered in a 350°F oven until hot, or slice and gently reheat in a skillet with the juices.
How long does Onion Boil take?
About 1 hr 15 min in total: 10 min prep and 1 hr 5 min cooking.
What do I need to make Onion Boil?
The key ingredients are sweet onions, butter, paprika, garlic powder, dried thyme and cayenne pepper, plus pantry basics.
Any tips for Onion Boil?
A deep cut through the base releases the butter before the center softens; keep the bottom of the onion whole.
