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 polyphenols. Studies have shown that polyphenols are beneficial to our health. It’s nice that something so flavorful is also very 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):
- Red onion.
- Olive oil.
- Kosher salt: If using fine salt, you might want to reduce the amount you use.
How to roast red onions
It’s so easy! Scroll down to the recipe card for the detailed instructions. Here are the basic steps:
- Peel the onion, slice into slices and separate the slices into rings.
- Spread the onion rings in a baking dish. Toss with olive oil and sprinkle with salt.
- 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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Roasted Red Onions
- 1 large red onion
- 2 tablespoons olive oil
- 1/2 teaspoon kosher salt
- 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.