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Herb Baked Sweet Onions are a simple yet elegant side dish that adds big flavor to any meal. Whole sweet onions are brushed with a blend of olive oil, garlic, and fresh herbs, then baked until buttery and tender. The result is a savory-sweet, melt-in-your-mouth onion that is soft, with herby goodness in every bite.
Oven Roasted Onions with Garlic and Herbs
As they roast, the onions become incredibly tender, soaking up all that savory, herby flavor. This easy recipe makes a beautiful presentation and brings out the natural sweetness of the onions in the most delicious way.
This easy baked onion recipe is perfect for holiday dinners, Sunday roasts, or weeknight meals that need a flavorful vegetable side.
Why We Love This Recipe
- Simple Ingredients, Big Flavor – Just a handful of pantry staples and fresh herbs transform sweet onions into a savory, buttery side dish.
- Beautiful Presentation – These whole baked onions look elegant on the table, making them perfect for holidays and special occasions.
- Easy to Prepare – Minimal chopping and prep work make this a low-effort recipe with high-impact results.
- Versatile Side Dish – Serve alongside meats, pasta, potatoes, or enjoy chopped as a flavorful topping.
- Naturally Gluten-Free & Vegetarian – This roasted sweet onion recipe fits a variety of dietary needs.
These Herb Baked Sweet Onions are buttery, tender, and full of herby garlic flavor.
Baked onions are easy to make and go perfectly with Crispy Pan-Fried Chicken Cutlets or Easy Baked Pork Tenderloin, and much more!
I never craved roasted onions until I made this recipe! I could eat them as my main meal.
Ingredients in this Oven Roasted Whole Onions Recipe
Here’s what you’ll need:
• Sweet Onions
• Olive Oil
• Fresh Rosemary, minced
• Fresh Thyme, minced
• Fresh Parsley, minced
• Garlic – Fresh is best!
• Salt & Black Pepper
• Unsalted Butter (not pictured)
Variations & Substitutions
• Adjust for Quantity: Making more than five onions? Scale the oil, herbs, and butter as needed.
• Cheesy Version: Add shredded Parmesan or Swiss cheese during the final 10 minutes of baking.
• Balsamic Boost: Drizzle with balsamic vinegar before serving for extra depth.
• Use Ghee: Substitute butter with ghee for a slightly nutty richness.
• Crispy Topping: Sprinkle herbed breadcrumbs on top for the final 15 minutes of baking for texture.
How to Make the Best Baked Sweet Onions
Prep
• Heat oven to 400°F. Prep the herbs by mincing them.
• Cut the tops and bottoms off the onions and peel them. Score an “X” on the top of each onion about ½ inch deep. Place prepared onions in a baking dish.
• In a small bowl, combine olive oil, rosemary, thyme, parsley, pressed garlic, salt, and black pepper. Mix well.
• Brush the tops of the onions with the herb mixture, making sure to coat well. Spoon any leftover herbs on top.
• Add a pat of butter to the top of each onion.
Bake
• Cover the baking dish and bake for 50 minutes (Small onions may not need as much time).
• Uncover and bake for another 15 minutes.
• Serve each onion with a spoonful of the flavorful cooking liquid from the pan.
Tip:
You can cut the onions into halves or quarters before baking for faster cooking and easier portioning. Smaller pieces are also great for serving on top of meats, baked potatoes, burgers, or pasta dishes.
Baked Onions FAQs
What are people asking about how to roast onions?
- What kind of onions should I use for this recipe?
Use sweet onion varieties such as Walla Walla, Vidalia, or Maui. These have a naturally mild, sweet flavor that tastes amazing! - Can I make this recipe with yellow or white onions?
You can, they will just be a bit stronger and less sweet. You can mellow them by soaking in cold water for 10 minutes after peeling. - Can I prep these onions ahead of time?
Yes! You can peel and score the onions, and mix the herb oil mixture in advance. Assemble just before baking. - Can I make this baked onions recipe vegan?
Yes, simply swap the butter for a plant-based alternative like vegan butter or just omit the butter.
Serving Suggestions
These Herb Baked Sweet Onions pair beautifully with a wide range of main dishes. Their rich, savory flavor and tender texture complement everything from roasted meats to vegetarian mains. Here are some ideas:
- Serve whole alongside roast chicken, steak, or pork tenderloin.
- Slice and spoon over mashed potatoes, steak bites, or roast beef sandwiches.
- Chop and mix into grain bowls, potatoes, or use as a topping for baked potatoes.
- Pair with other roasted vegetables for a cozy fall or winter platter.
More Easy Vegetable Side Dish Recipes
Instant Pot Mashed Cauliflower
Easy Sautéed Green Beans
Creamy Dill Cucumber Salad
Flavorful Boiled Corn on the Cob
Slow Cooker Garlic Herb Potatoes
Storage
Place leftover baked onions in an airtight container in the refrigerator for up to 4 days. Reheat in the oven or microwave.
If you make this delicious Herb Baked Sweet Onions recipe, let me know! Leave a comment with a star rating below. I’d love to hear from you!
Herb Baked Sweet Onions
Equipment
- Baking Dish with Lid (or use a foil lid)
- Brush or Spoon
Ingredients
- 5 Sweet Onions (see notes)
- ¼ cup Olive Oil
- 1 Tablespoon Fresh Rosemary, minced
- 1 Tablespoon Fresh Thyme, minced
- 2 Tablespoons Fresh Parsley, minced
- 2 cloves Garlic
- ½ teaspoon Salt
- ½ teaspoon Black Pepper
- 5 Tablespoons Unsalted Butter (or 1 Tbsp. per onion)
Instructions
Prep
- Heat oven to 400°F. Prep the herbs by mincing them.
- Cut the tops and bottoms off of the onions and peel them. Then score them in an X shape about ½ inch deep. Place in the baking dish. Set aside.
- To a small bowl, add the olive oil, rosemary, thyme, parsley, garlic, salt, and black pepper.
- Using a garlic press, add the garlic to the bowl with the oil & herbs. Mix together well.
- Brush the tops of the onions with the herbed oil mixture and spoon the herbs on top of each onion. Use all of it.
- Place a pat of unsalted butter on top of each onion.
- Place the lid on the baking dish and bake for 50 minutes. Then remove the lid and bake another 15 minutes.
- Serve each onion with some of the liquid from the baking dish.
Notes
Sweet Onion Types
- Walla Walla Sweets, Vidalia, Maui, or any onion labeled as 'sweet' will work.
- Try to get them in similar sizes for even cooking time.
- Use as many onions as you want, though more than 5 may require a bit more of the oil/herb mixture, and butter.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
these look delicious! thank you on my list of cooking!
I had a recipe for these baked onions but I can see this one
is much better. Going to make this soon. Looks amazing!