An easy recipe for roasted red onion slices. Roasting removes any bitterness, so the onions are mellow and creamy.
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 creamy baked onions and red onion confit. Pickled red onions are good too, although that’s indeed more of a condiment.
Cooking makes a big difference
These roasted red onions are wonderfully mellow and creamy. It’s like magic! Roasting takes the onions from bitter and pungent to mild and caramelized, almost sweet.
The same thing happens when roasting garlic. The sharpness is replaced with wonderful creaminess.
The ingredients needed for this recipe
You only need three simple ingredients to make roasted red onions (the exact amounts are listed in the recipe card below). Don’t you just love recipes with a short ingredients list? Here’s what you’ll need:
Red onion: I haven’t tried making this recipe with white or with yellow onions. You can try using yellow onions. But the white ones are very sharp – I don’t know if they’re good candidates for this recipe.
Olive oil: This is my favorite oil. But if you’re unsure about cooking with it, you can use avocado oil instead. It has a higher smoke point.
Kosher salt: If using fine salt, you might want to reduce the amount you use or the dish could end up too salty.
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 it 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. That’s it! Super easy. And so tasty!
How to cut the onions
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 them 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 also add a bit of balsamic vinegar – 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 love being able to 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
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.
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Vered DeLeeuw, LL.M., CNC, has been following a low-carb real-food diet and blogging about it since 2011. She's a Certified Nutrition Coach (NASM-CNC), has taken courses at the Harvard School of Public Health, and has earned a Nutrition and Healthy Living Certificate from Cornell University. Her work has appeared in several major media outlets, including Healthline, HuffPost, Today, Women's Health, Shape, Reader's Digest, and Better Homes and Gardens.