Gluten-Free/ Vegetables/ Vegetarian & Vegan

Whole Roasted Onions In Foil

A simple and delicious vegetable side dish that is full of flavor. These whole roasted onions in foil are ready to roast in just 5 minutes and are perfectly creamy and soft.
Two roasted onions wrapped in foil

Last Updated on September 10, 2020 by Betty Davies

Onions have never tasted so good! These whole roasted onions are wrapped in foil to be cooked and the result is the most buttery side dish that is loaded with flavor. So quick and easy to prep and just a few ingredients needed. Vegetarian and gluten-free.

Two roasted onions in a baking tin surrounded by foil

Onions are one of my favorite vegetables, but rather than using them to add flavor to the dish, with this recipe they can be a side in their own right!

They are super delicious and come out perfectly buttery, tender and full of flavor. They are fancy enough to serve to company on special occasions, but simple enough to make you can enjoy them as part of a weeknight family meal.

Why you will love these roasted onions!

  • Hands off: It takes no more than 5 minutes of prep time and the cook time is totally hands off, leaving you to get on with other things.
  • Simple ingredients: Nothing fancy here, you can whip up these onions without needing a special trip to the store.
  • Easy: This side is so easy you have to give it a try! You don’t even have to peel the onions!

Ingredients

  • Onions: For this recipe I used sweet onions (Vidalia), but you can easily use red or yellow onions instead.
  • Oil: I like to roast with olive oil as that rich flavor seeps into each bite. You can use neutral oils like grapeseed or canola, but you won’t get that extra bit of flavor.
  • Butter: I prefer to use salted butter. If you use unsalted, just add a pinch of salt to the top of each onion.
  • Thyme and Rosemary: Fresh thyme and rosemary add a wonderful subtle herby and earthy flavor. If you are in a pinch, you can use dried herbs.
A quarter of a roasted onion on a serving plate

How to roast whole onions in foil

Be sure to scroll down for the full recipe!

  • Cut the tops and bottoms off of the onions.
  • Place on foil, drizzle with oil and top with butter and herbs (photo 1).
  • Wrap in foil and roast until they are soft and buttery (photo 2).
Process shots to show how to roast whole onions

Recipe Variations

These whole roasted onions are pretty awesome as they are, but you can easily make them to your taste:

  • Mix up the herbs. Sage, oregano and tarragon will all work well.
  • Make it vegan by omitting the butter or using a diary-free brand.
  • Add a couple of crushed garlic cloves for an extra hit of extra flavor.
  • Add some chili flakes if you like a bit of heat.
  • Drizzle over some balsamic vinegar.

Frequently Asked Questions

How long do you roast onions?

It will take around an hour for the onions to roast, but of course, this will depend on the size of the onions you are using. I used pretty large onions and they took just over an hour, if you are using smaller ones, give them a check after 50 minutes.

Can you make them ahead of time?

These onions are best served soon after you’ve roasted them so that they don’t dry out. You can leave them wrapped in the foil up to an hour before you want to serve them to keep them warm. If you want to reheat them, just keep them wrapped in foil and place in the oven at 350F / 180c for 10 to 15 minutes to warm through.

Do you have to peel the onions?

No! You just need to top and tail the onions, be sure to keep that skin on! The skin protects the flesh of the onion and helps to keep the moisture in. When you are ready to serve just remove the skin, which will come off pretty easily.

A whole roasted onion on a serving plate

Serving Suggestions

These onions will work pretty well with most meals, but here are my favorite options:

Recipe Notes and Tips

  • Do not remove the skin of the onions, it will help protect the flesh from the heat.
  • Don’t wrap the foil too tightly. Tent it to let the air circulate.
  • Cooking times will vary depending on the size of your onions.
  • The onions are done when they are fork tender.

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Two roasted onions wrapped in foil

Whole Roasted Onions In Foil

A simple and delicious vegetable side dish that is full of flavor. These whole roasted onions in foil are ready to roast in just 5 minutes and are perfectly creamy and soft.
5 from 1 vote
Print Pin Rate
Course: Side Dish
Cuisine: American
Diet: Gluten Free, Vegetarian
Prep Time: 5 minutes
Cook Time: 1 hour
Total Time: 1 hour 5 minutes
Servings: 8 servings
Calories: 61kcal
Author: Betty Davies

Ingredients

  • 2 large onions
  • 2 tablespoons oil
  • 2 tablespoons butter
  • 6 sprigs thyme
  • 4 sprigs rosemary
  • black pepper and fresh parsley to serve (optional)

Instructions

  • Pre heat the oven to 460F / 240c.
  • Cut the tops and bottoms off of the onions and lay them on separate sheets of foil, cut side up.
  • Pour a tablespoon of oil on top of each onion, and then a tablespoon of butter on top.
  • Sprinkle some fresh thyme and rosemary leaves on top of each onion and place the left over sprigs around the base.
  • Wrap the foil around the onions. Tent it so that they are not super tightly wrapped to let the air circulate.
  • Place in the oven for an hour until they are soft and buttery.
  • Brush off the roasted herbs, remove the skins and sprinkle with some freshly ground black pepper and some fresh parsley.

Notes

  • Do not remove the skin of the onions, it will help protect the flesh from the heat.
  • Don’t wrap the foil too tightly. Tent it to let the air circulate.
  • Cooking times will vary depending on the size of your onions.
  • The onions are done when they are fork tender.

Nutrition

Calories: 61kcal | Carbohydrates: 7g | Protein: 1g | Fat: 4g | Saturated Fat: 1g | Cholesterol: 1mg | Sodium: 11mg | Potassium: 108mg | Fiber: 1g | Sugar: 4g | Vitamin A: 36IU | Vitamin C: 5mg | Calcium: 24mg | Iron: 1mg

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1 Comment

  • Reply
    Healthy World Cuisine
    September 24, 2020 at 7:53 pm

    5 stars
    Love this idea! So simple but so delicious! Now that the weather is warming up, we can imagine how delicious your roasted onions would go so well with so many fall cozy recipes.

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