An easy recipe for roasted red onions. Baking them in the oven removes any bitterness, so the onions are mellow and creamy.
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. In both cases – onions and garlic – I’m not a fan of the raw vegetable. But the cooked is absolutely delicious!
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 and I love cooking with it. But if you’re unsure about cooking with it, you can use avocado oil instead. It has a higher smoke point. Another tasty option is using melted butter.
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. The video below in the recipe card shows you how I do it.
2. Spread the onion rings in a baking dish. Toss them with some olive oil and sprinkle them with kosher 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.
What to do with leftovers?
You can keep the leftovers in the fridge, in a sealed container, for 3-4 days. They can be reheated in the microwave, and they taste great – just as good as fresh. I also like to add them the next day to an omelet, or even (cold) to a salad.
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Roasted Red Onions
- 1 large red onion
- 2 tablespoons olive oil
- 1/2 teaspoon Diamond Crystal kosher salt
- Preheat your 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 the onion rings with salt.
- Roast the onions, stirring once halfway through roasting, until soft and caramelized, about 20 minutes.