These roasted onions are flavorful and caramelized. They're the perfect side dish or topping for meat and poultry. Even if you're not a fan of onions in their raw state, I think you will love them oven-baked. They are mellow and sweet.
These roasted onions are easy to make, and they are so delicious. They are also versatile - you can use them to top steaks and burgers or as a savory side dish. Raw onions are sharp, but something magical happens when you cook them. They become creamy and mild, almost sweet. It's true for baked onions, sauteed onions, and caramelized onions.
Ingredients
You'll only need three ingredients to make this recipe. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:
- Medium onions: White or yellow onions work well in this recipe (here's the difference between onion types), although I usually use yellow ones.
- Butter: I use plenty of butter - two tablespoons per medium onion plus more for the pan. The butter greatly enhances this dish.
- Kosher salt: I use Diamond Crystal kosher salt, by far my favorite salt to cook with.
Variations
- Since onions are inherently flavorful, I don't usually add any other seasonings. But if you'd like, you can season them with garlic powder and oregano, using ¼ teaspoon of each. You can also sprinkle them with freshly ground black pepper, as shown in the photo below.
- After flipping, you can sprinkle the onions with two tablespoons of grated parmesan cheese.
- You can coat the onions with extra-virgin olive oil instead of butter. In the photo below, I used olive oil with excellent results.
Instructions
Scroll down to the recipe card for detailed instructions. Here's an overview of the steps for making this recipe:
Peel the onions, slice off their edges, and cut them into five ¼-inch slices. Place the onion slices in a well-buttered, rimmed baking dish. Coat them with melted butter and sprinkle them with Kosher salt.
Bake the onions until golden brown. This should take about 40 minutes in a 400°F oven. Flip the slices midway through baking.
Serve immediately. Aren't they gorgeous? But I wish you could smell them! They smell so good.
Featured Comment
Like onion rings without the breading, and MUCH less work! I oven-roasted a sheet pan of several different vegetables to go into a casserole that I planned to make. Had my husband (big onion-rings fan) try one of these onion slices, and he wanted to eat them all (and did)! - Home Cook Read more comments
Recipe Tips
- Keep a close eye on the onions during the last ten minutes of baking to make sure they don't burn. Your oven might run hotter than mine. Their edges should be dark brown, not black.
- You can double this recipe, roast two onions, and use a 9 X 13-inch Pyrex pan or a parchment-lined rimmed baking sheet.
Recipe FAQs
We don't often think about onions as a separate side dish. We tend to use them as an ingredient in other recipes. But in this case, they make a delicious side dish!
Yes. You can replace the butter with olive oil. If you can tolerate ghee (clarified butter), that's another delicious option. It adds a pleasant, nutty flavor.
Yes. You can use them in this recipe or check out this recipe for roasted red onions.
Serving Suggestions
Roasted onions pair well with meat and poultry. Since I bake them in a 400°F oven, I like to serve them with a main dish I can cook in the same oven. So, among other choices, I often serve them with baked pork chops, baked meatballs, or beef tenderloin roast.
They also make the perfect topping for hamburgers and steaks, including broiled hamburgers, turkey burgers, bison burgers, tri-tip roast, New York strip steak, and ribeye steak.
Storing Leftovers
You can keep the leftovers in a sealed container in the fridge for 3-4 days. Reheat them, covered, in the microwave at 50% power.
Alternatively, chop the leftovers and mix them into an omelet or a scramble, such as spinach and eggs scramble, fluffy scrambled eggs, or egg white omelet. The photo below shows a scramble made with the leftover onions and served with avocado.
Recipe Card
Buttery Roasted Onions
Video
Ingredients
- 2 tablespoons butter - plus more for the pan
- 1 medium onion
- ½ teaspoon Diamond Crystal kosher salt - see notes below
Instructions
- Preheat the oven to 400°F. Grease a square 8-inch Pyrex baking dish with butter.
- Peel the onion and slice it into ¼-inch-thick slices. You should get five slices.
- Arrange the slices in a single layer in the prepared baking dish. Melt the butter and pour it over the onions. Sprinkle them with kosher salt.
- Roast the onions until the bottoms are golden, about 20 minutes.
- Turn the onion slices to the other side and bake them until golde brown, about 20 more minutes.
- Serve immediately.
Notes
- If using any salt other than Diamond Crystal Kosher Salt, including Morton kosher salt, use half the amount listed.
- You can double this recipe and use a 9 X 13-inch Pyrex pan or a parchment-lined rimmed baking sheet.
- Keep a close eye on the onions during the last 10 minutes of baking to make sure they don't burn. Your oven might run hotter than mine. Their edges should be deep brown, not black.
- Since the onions are so flavorful, I don't add any other seasonings. But if you'd like, you can season the onions with garlic powder and oregano, using ¼ teaspoon of each. You can also sprinkle them with grated parmesan cheese after flipping them.
- You can keep the leftovers in a sealed container in the fridge for 3-4 days. Reheat them, covered, in the microwave at 50% power. Alternatively, chop the leftovers and mix them into an omelet or a scramble.
Nutrition per Serving
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Disclaimers
Most recipes are low-carb and gluten-free, but some are not. Recommended and linked products are not guaranteed to be gluten-free. Nutrition info is approximate. Please verify it independently. The carb count excludes non-nutritive sweeteners. Please read these Terms of Use before using any of my recipes.
Home Cook says
Like onion rings without the breading, and MUCH less work! I oven-roasted a sheet-pan of several different vegetables to go into a casserole that I planned to make. Had my husband (big onion-rings fan) try one of these onion slices, and he wanted to eat them all (and did)!
Vered DeLeeuw says
I'm so glad this was a success! Thank you very much for taking the time to write a review. I appreciate it.
Amanda says
Easy and delicious. Perfect for burgers. I like to mix the leftover into mashed potatoes. Yum!
Vered DeLeeuw says
I'm glad you liked this recipe, Amanda! Thanks for the comment.