Rosemary Roasted Onions
These rosemary roasted onions are a simple side dish with bold flavor! As the onions roast in the oven, they are infused with aromatic rosemary and become sweet with the best caramelized edges.
There is just something about roasted vegetables that are so simple but so delicious at the same time! You can use them as a side dish, for meal prep and everyone loves them for special occasions.
These rosemary roasted onions are a favorite and I first learned to make them from my mother-in-law who roasted them on a wood-burning stove. Luckily for us, we can achieve the same result by oven-roasting.
Oven-roasted onions are tender, sweet and have the best buttery texture. Roasting them adds to their caramelized taste just like in my favorite Italian roasted peppers or candied roasted tomatoes.
Why You Will Love Roasted Onions
- Easy to make: This simple roasted onions prep in only minutes then roast hands off in the oven.
- Flavorful: Oven-roasted onions have a mild, sweet and savory taste with a herbaceous rosemary flavor profile!
- Versatile: Serve as a side dish, add to a holiday table or for onion lovers to eat on their own!
Ingredients
- Onions: While any onion works, yellow onions or sweet onions are best.
- Garlic: Freshly minced cloves of garlic add the best flavor.
- Seasonings: Dried oregano, salt and fresh rosemary sprigs.
Substitutions And Variations
- Roast in muffin pan: For smaller onions, roasting them in a muffin pan is a fun presentation and results in the best charred edges.
- Other herbs: While rosemary is a favorite, you can use oregano or sage. Fresh thyme roasted onions are wonderful as well.
- Balsamic vinegar: Drizzle with some balsamic vinegar before roasting the onions.
- Rich taste: Add some melted butter along with the olive oil.
- Additional vegetables: Add in other root vegetables like potatoes or sweet potatoes.
How To Roast Onions
To start, lightly oil or line a baking dish with parchment paper. Place onions cut side up in a single layer in a prepared shallow baking dish.
Sprinkle with minced garlic, oregano, salt, chopped rosemary and drizzle with olive oil.
Bake until onions are tender and dark golden brown. Serve caramelized onions immediately.
Expert Tips
- Keep extra onions on hand: Just in case you slice into one and find that the inner layer is beginning to spoil.
- Similar sized onions: To roast onions evenly, choose onions that are roughly the same even size.
- Don’t overcrowd the pan: Otherwise your onions will steam instead of become caramelized.
- Avoid burnt onions: Overbaking the roasted onions will lead to dry, burnt results. A few charred bits are okay, overly burnt onions not so much.
- Peel the skin of the onion: Either before or after roasting. The papery skin does not have the best taste.
Serving Suggestions
Roasted onions are delicious right out of the pan but you can also use them in so many more ways!
- Add as a topping: Add to salad, top Parmesan crusted burgers or even an Italian sliced beef pizzaiola.
- Side Dish: Pair with a main dish such as Italian herb roasted chicken or Italian sheet pan pork chops.
- Pasta: Add as a flavor booster to pasta recipes.
- Breads: Top Italian frittelle or even pizza dough for a simple appetizer.
- Add-in: Add to mashed potatoes, soups, scalloped potatoes or even Italian meatloaf.
Storing Leftovers
Store: Cool roasted onions completely then transfer to an airtight container and store in the refrigerator for 3 to 5 days. Reheat or enjoy them cold on salads, in wraps or use them in French onion soup.
Freeze: Freeze cooked onions by first flash freezing them on a parchment paper lined pan. Then transfer to a freezer safe bag and store them for up to 1 year. Thaw in the refrigerator before reheating and serving.
Recipe FAQs
While I love any onions roasted, including red onions and white onions, yellow onions or Vidalia onions work best! Yellow onions have a strong flavor when raw but that mellows into a subtle sweet taste when making oven-roasted onions. They also hold up well to high heat.
Slice onions in half vertically from the tip to the root.
While this roasted onion recipe is best oven-roasted in halves, it is possible to roast them whole or quartered. Roast in wedges (quartered onions) by first peeling them and then flip halfway through roasting time. To roast whole onions, peel and cut off the ends. Bake for up to 80 minutes covering the onions if they brown.
Both! While onions are often used as a topping or a stand alone ingredient they can entirely stand on their own as a flavorful side dish.
More Vegetable Side Dishes
- Sauteed Chicory Greens
- Roasted Zucchini and Potatoes
- Italian Pan Fried Tomatoes
- Italian Grilled Pepper Appetizer
- Zucchini Patties
These delicious Roasted Onions make the perfect side dish for any occasion. Buon Appetito!
Rosemary Roasted Onions
Ingredients
- 3 large onions sliced in half (centre cut in half)
- 1-2 cloves garlic minced
- 3 tablespoons olive oil
- 1 teaspoon oregano
- ½ teapoon salt or to taste
- 1-2 tablespoons fresh rosemary sprigs chopped
Instructions
- Pre-heat oven to 425F (210C). Lightly oil or line with parchment paper a medium baking dish.
- Place cut side up onions in a single file in baking dish, sprinkle with minced garlic, oregano, salt, chopped rosemary and drizzle with olive oil.
- Bake for approximately 30-30 minutes or until onions are tender and dark golden brown. Serve immediately. Enjoy!
Notes
Nutrition
Updated from December 15, 2016.
These look delicious. It looks like you have parchment paper in the bottom of your baking dish, but I don’t see that in your instructions. Would you recommend using parchment paper over lightly oiling the dish?
Hi Penny, yes sometimes I do sometimes I don’t line it with parchment paper, you can do either, it’s probably better parchment paper though that way the onions won’t stick at all. Let me know how it goes. I added that into the recipe instructions, thanks.
Thanks for introducing them to me. Awesome sweet side dish!
Hi Diana, so glad you enjoyed them. Have a great long weekend. 🙂
The perfect delicious side dish, thanks for sharing.