Roasted Red Onions

An easy recipe for roasted red onion slices. Roasting removes any bitterness, so the onions are mellow and creamy.

Roasted red onions are mellow and creamy. It’s like magic! Roasting takes the onions from bitter and pungent to mild and caramelized, almost sweet.

Onions make a great side dish

We don’t usually think about onions as a side dish. We mostly use them as a condiment, as a way to season our food.

But onions can be a great side dish. I have several on this blog, including these roasted red onions, creamy baked onions, and red onion confit. Pickled red onions are good too, although that’s indeed more of a condiment.

Onions are healthy

Onions are rich in the antioxidants known as polyphenols. Studies have shown that these antioxidants have many properties that are beneficial to our health. It’s nice that something to flavorful is also so healthy!

The ingredients needed for this recipe

You only need three ingredients to make this tasty side dish (exact amounts are listed in the recipe card below):

1. Red onion
2. Olive oil
3. Kosher salt

How to roast red onions

It’s so easy! Scroll down to the recipe card for the detailed instructions. Here are the basic steps:

1. Peel the onion, slice into slices and separate the slices into rings.
2. Spread the onion rings in a baking dish. Toss with olive oil and sprinkle with salt.
3. Roast at 400°F until soft and caramelized, about 20 minutes.

How do you cut red onions for roasting?

Scroll down to the recipe card for the detailed instructions. But basically, you wash, dry and peel the onions. Then slice them into 1/4-inch thick slices and separate the slices into rings. You can also cut them into quarters if you prefer and roast for a little longer.

Can I caramelize red onions?

Yes. High heat roasting as we do here caramelizes the onions. To promote caramelizing, you can add a bit of balsamic vinegar too – about 1/2 tablespoon. The sugar in the aged vinegar will help the onions to caramelize.

How to serve roasted red onions

They make a delightful side to any meat dish, and especially to grilled meats. I often serve them with grilled chicken tenders. They are also excellent with crispy baked chicken thighs, and I can roast both in the same oven.

What about leftovers?

You can keep leftovers in the fridge, in a sealed container, for 3-4 days. I like to add them the next day to an omelet. 

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4.91 from 40 votes

Roasted Red Onions

An easy recipe for roasted red onion slices. Roasting removes any bitterness, and the roasted red onions are mellow and creamy. Great with grilled meats!

Prep Time10 mins

Cook Time20 mins

Total Time30 mins

Course: Side Dish

Cuisine: American

Keyword: onion

Servings: 2 servings

Calories: 148kcal

Author: Vered DeLeeuw

INGREDIENTS

• 1 large red onion
• 2 tablespoons olive oil
• 1/2 teaspoon kosher salt

INSTRUCTIONS

• Preheat oven to 400 degrees F.
• Peel the onion, slice into 1/4-inch thick slices and separate the slices into rings.
• Spread the onion rings in a glass baking dish. Add the olive oil and toss to coat. Sprinkle with salt.
• Roast the onions, stirring once halfway through roasting, until soft and caramelized, about 20 minutes.

NUTRITION INFO Nutrition info is approximate. It is calculated using the SparkPeople.com recipe calculator, and the carb count excludes sugar alcohols. Please read the disclaimers in our Terms of Use carefully before using any of our recipes. Recommended and linked products are not guaranteed to be gluten-free. Please verify they are before using.

Nutrition Facts

Roasted Red Onions

Amount Per Serving

Calories 148 Calories from Fat 117

% Daily Value*

Fat 13g20%

Saturated Fat 2g13%

Sodium 282mg12%

Carbohydrates 6g2%

Fiber 1g4%

Protein 1g2%

* Percent Daily Values are based on a 2000 calorie diet.

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