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Roasted Onions make any dinner extra delicious! Tender and caramelized but just a little bit crispy on the edges, these onions will add loads of sweet-and-savory flavor to meats, salads, meal bowls, and more.

Overhead view of roasted onions on plate

Why You’ll Love This Oven-Roasted Onions Recipe

  • Quick Alternative to Caramelized Onions. Everyone loves caramelized onions, but hello, who has 45+ minutes on a weeknight to caramelize them properly? (Psst—never believe any recipe that tells you to caramelize onions over medium-high heat for 5 minutes. It’s a lie!) This roasted onions recipe delivers lots of flavor and it cooks in half the time.
  • Sweet-Savory Balance. Let’s talk more about that flavor! While caramelized onions go all in on sweet, roasted onions have a more balanced flavor; the roasting intensifies the sweetness of the onions, but they still pack in lots of savory goodness.
  • Crispy and Tender. Baked onions get tender and caramelized, but the edges also get some crispy char on them, which makes them an absolute delight. It’s similar to how Roasted Brussels Sprouts have those contrasting tender centers and crispy outer leaves.
  • Add Them to EVERYthing. From Crustless Quiche to Grilled Pork Tenderloin and even No Knead Focaccia, everything tastes better with thyme-infused oven-roasted onions.
  • The Best Way to Use Spare Onions. You know how some stores only sell onions in bags? And then you have a WHOLE BAG of onions when you really just needed one for your Homemade Chicken Noodle Soup? Roasted onions (and Roasted Radishes) are an excellent way to use up an extras.
Overhead view of roasted onions on sheet pan

How to Make Roasted Onions

The Ingredients

  • Onions. You can use red or yellow onions. Sweet onions like Vidalia, while delicious sliced on Air Fryer Hamburgers, are not ideal here because their higher water content will make them bake up mushy.
  • Dijon Mustard. For some pep and zip. Mustard has a sharpness that works well as a complement to the sweetness of the roasted onions.
  • Dried Thyme. Thyme is a classic pairing with onions (and also other roasted vegetables like Roasted Mushrooms and Roasted Butternut Squash).

Substitution Tip

You can flavor roasted onions with any herbs you like or have on hand; woody fresh herbs like thyme or rosemary can be added to the pan while baking, too. 

Parmesan cheese is also delicious on these onions. Add freshly grated Parm during the last 5 minutes of cooking time and it will melt over the roasted onions, adding some umami and nuttiness. Yum!

The Directions

Overhead view of halved onion on cutting board
  1. Get Started. Peel and halve the onions.
Two onion halves sliced into wedges
  1. Cut into Wedges. Slice each onion into four wedges.
Seasoned onions on sheet pan
  1. Season. Toss the onion wedges with the remaining ingredients.
Roasted onions on sheet pan
  1. Roast. Bake onions at 425 degrees F for 25 to 35 minutes, flipping halfway through. Season with salt and ENJOY!

Recipe Variations

  • Balsamic Roasted Onions. Instead of Dijon mustard, whisk balsamic vinegar with the oil.
  • Roasted Onion Slices. While I love onion wedges as a side dish, onion slices work better for piling onto a burger or sandwich. Cut 1/2-inch slices of onion and roast for 20 to 25 minutes.
Closeup of roasted red and yellow onions on plate

Leftover Ideas

Leftover roasted onions are excellent added to an Egg White Frittata or Sweet Potato Hash for breakfast. You can make them into another dinner by serving leftovers atop a bowl of Farro Risotto or Creamy Polenta.

What to Serve with Roasted Onions

Roasted onions on plate

Recipe Tips and Tricks

  • Use Onions That Are Similar in Size. It’s okay if you don’t have medium onions! You can use all small onions or all large onions and adjust the time accordingly. But don’t use a small onion and a large onion—the large onion wedges will still have the bite of raw onion while the small wedges are burning.
  • Leave Room for Air Circulation. AKA: Don’t crowd the pan! When you pack your vegetables together, whether you’re making Roasted Cauliflower or Roasted Asparagus, they’ll end up steaming instead of roasting. This means the texture and flavor will be womp womp. Spread the onions on the pan and give them some space.
  • It’s Okay if the Wedges Fall Apart. Roasted onions are all about contrasting flavors and textures; the wedges that fall apart will be crispier, which is a nice contrast to the softer, less-charred onions that stay intact.
  • Season Evenly. Make sure the onions are well-coated with the oil and mustard. It’s not just for flavor, but the oil is what helps the onions achieve those perfect crispy edges in the oven.

Roasted Onions

5 from 5 votes
Roasted onions are an easy side that goes with just about anything! Tender with crispy edges and the perfect balance of sweet and savory.

Prep: 5 minutes
Cook: 35 minutes
Total: 40 minutes

Servings: 3 -4 servings



  • Place a rack in the center of your oven and preheat to 425°F. Line a large rimmed baking sheet with parchment paper.
  • Halve each onion through its stem ends. Trim off the tip of each stem and remove the peel. Cut each half lengthwise into 3/4- to 1-inch wedges (you will have about four wedges per half). Place in the center of the baking sheet.
  • Whisk together the remaining ingredients in a small bowl. Pour the oil mixture over the top and gently to coat the onions evenly. Some of the wedges will fall apart, which is fine. Spread into a single layer so that the cut sides of the wedges are touching the sheet pan.
  • Roast onions for 25 to 35 minutes, until the onions are tender and lightly charred at the edges, using a spatula to flip them once halfway through. Season with a pinch of additional salt. Enjoy warm or at room temperature.


  • TO STORE: Refrigerate leftovers in an airtight container in the refrigerator for up to 4 days.
  • TO REHEAT: Reheat roasted onions in a 350 degree F oven until warmed through, in a nonstick skillet set over medium-low heat, or in the microwave.
  • TO FREEZE: Freeze leftovers in an airtight container or zip-top freezer bag for up to 2 months. Thaw overnight in the refrigerator, then reheat as directed above.


Serving: 1(of 3)Calories: 114kcalCarbohydrates: 7gProtein: 1gFat: 9gSaturated Fat: 1gPolyunsaturated Fat: 1gMonounsaturated Fat: 7gPotassium: 113mgFiber: 1gSugar: 3gVitamin A: 10IUVitamin C: 6mgCalcium: 22mgIron: 0.5mg

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Erin Clarke

Hi, I'm Erin Clarke, and I'm fearlessly dedicated to making healthy food that's affordable, easy-to-make, and best of all DELISH. I'm the author and recipe developer here at and of The Well Plated Cookbook. I adore both sweets and veggies, and I am on a mission to save you time and dishes. WELCOME!

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  1. This recipe is a lifesaver! I’m always looking for easy and healthy side dishes, and this hits the spot perfectly. I love that it’s so versatile too. Made these with a sprinkle of smoked paprika and they were divine! It added extra flavor that we like. Thank you so much!5 stars

  2. Perfect timing! I just picked up a giant bag of onions at the farmer’s market and was looking for ways to use them up. I made some changes, I used balsamic vinegar instead of olive oil and they were amazing! The tangy sweetness was perfect.5 stars

  3. Just made this to go with our dinner and I’m OBSESSED! My teenagers don’t usually like onions, but they actually ate these. Thanks for sharing!5 stars