These easy roasted sweet potatoes with red onions are the best you'll try! Perfectly tender and creamy in the center with well-browned, caramelized edges. A few tips make all the difference, be sure to read below for how to roast sweet potatoes.

Diced sweet potatoes and onions roasted in cast iron pan

It doesn't matter what time of the year or what season, I am happy to heat up the oven for some hearty roasted veggies. Some of my go-tos are: Italian roasted vegetables, Mediterranean-style roasted eggplant, roasted cauliflower, or roasted butternut squash, done up with a little lime vinaigrette and crunchy nuts (a must-try)!

But roasted sweet potatoes--tender and creamy on the inside and perfectly carmalized on the outside--are a whole category of delicious goodness!

I'm sharing my tested, tried-n-true recipe for roasted sweet potato cubes, tossed in extra virigin olive oil and cooked with some red onions, and a little pinch of cinnamon and allspice, which truly play up the earthy sweetness of the sweet potatoes.

Before getting to the roasted sweet potato recipe, let's cover just a few basic questions.

Diced sweet potatoes and onions roasted in pan
How to pick a good sweet potato? And how to store them

There are 16 varieites of sweet potatoes. Go for jewel or garnet sweet potatoes, which are the ones with the deep orange flesh. They tend to be moist and more tender, perfect for roasting or in casserole.

Look for small to medium size sweet potatoes, the larger they are the starchier they become. And make sure the skin is tight, unwrinkled, and there are no signs of bruising.  

Store raw sweet potatoes in a cooler, dry and dark location with good ventilation.

How to cut a sweet potato for roasting?

Cutting sweet potatoes into 1-inch chunks or cubes is a great way to prepare them for roasting. They turn out crispy on the outside, but still substanial and creamy on the inside.

First, peel the sweet potato. Trim the top and bottom, then cut the spuds into round slices. Cut each slice into 1-inch cubes or chunks. Remember that cutting them as evenly and close in size as possible will enusre they all cook in the same amount of time.

Should I boil the seet potatoes for roasting?

No. You do not need to boile sweet potatoes before roasting. And actually, you should not. For perfectly roasted sweet potatoes, start with raw cubes and toss them in a little extra virgin olive oil, then let the hot oven do the work of cooking them and concentrating their sweetness.

How long does it take to roast sweet potatoes?

Temprature and time play an important role in getting your sweet potatoes roasted just right.

Roast sweet potatoes at 400 degrees F.
The sweet potatoes will take anywhere from 35 to 45 minutes. Yes, they can cook faster at 425 degrees F or 450 degrees F, but the longer timeperiod is just what you need to truly cook the interior of the sweet potatoes until nice and creamy, while perfectly concentrating their sweetness.

Remember to flip the sweet potato cubes over partway through roasting.

How to Roast Sweet Potatoes: 5 Important Tips

As simple as oven roasted sweet potatoes are, a few tips have made all the difference for me:

1- Cut Sweet Potatoes into Cubes. I like to cut my sweet potatoes into 1-inch cubes. This is a good size, not too large and not too small. And they'll work nicely as a side dish, or you can add them to dinner bowls or to augment a salad. I'm not 100% precise, but I do try to cut the sweet potatoes into evenly sized pieces so they can take the same time to cook.

Freshly diced sweet potatoes and onions seasoned in mixing bowl

2- Set the Oven to 400 degrees F (approx 205 degrees Celsius.)  High heat is ideal for roasting vegetables, but, like I said earlier, choosing 400 degrees F as opposed to 425 degrees F or 450 degrees F will mean a longer cooking time, enough to coax more of the sweet potatoes natural sweetness out. It's also ideal for caramelizing the onions we're cooking along, without burning them.

3- Use a Generous Drizzle of Extra Virgin Olive Oil. Coating the sweet potatoes in olive oil is really what helps them crisp up well on the outside. And I always use a quality good-tasting oil because it does add flavor complexity to roasted veggies. This time, I used Private Reserve Greek extra virgin olive oil (you can find it at our online shop)

Freshly diced sweet potatoes and onions in baking pan

4- Season Sweet Potatoes Well. Yes, all you need is a generous dash of kosher salt and black pepper. But you can add more flavor to your liking. I went for a Middle Eastern/Persian vibe here with a bit of cinnamon and allspice, which really play up the earthiness of sweet potatoes.

You'll  notice in the photo above that I like to season my sweet potatoes in a bowl first before transferring to a baking dish. The bowl allows me to give the veggies a good toss and make sure they are well coated with the seasonings and oil (just a more even result.)

5- Use a Dark Sheet Pan or Baking Pan. Whenever possible, I like to use my cast iron baking pan for roasting vegetables. The dark helps the veggies cook well, while cast iron provides the added benefit of even, steady heat, making it easy for the veggies to char.

And, of course, do not crowd the baking pan. If you want things to cook well to that perfectly charred point, make sure they are well spread.

Occasionally, toss the sweet potatoes and onions so they cook well on all sides (do this carefully, and use a pair of tongs to turn things over if you need to.)

Similar Recipes to Try:

Oven Roasted Sweet Potatoes with Honey Tahini and Sesame Seeds

Best Roasted Greek Potatoes

Crunchy Roasted Chickpeas

Baked Lamb Chops with Root Vegetables

Easy Ratatouille Recipe

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4.94 from 43 votes

Easy Cinnamon Roasted Sweet Potatoes

Suzy Karadsheh
Diced sweet potatoes and onions roasted in cast iron pan
Easy cinnamon roasted sweet potatoes with red onions. Using this recipe, the sweet potatoes turn out perfectly creamy in the center with well-browned, caramelized edges. The hint of cinnamon and caramelized red onions add more warmth and depth to these comforting sweet potatoes. 
Prep – 10 minutes
Cook – 35 minutes
Serves – 6


  • 3 lb sweet potatoes peeled and cut into 1-inch cubes
  • Extra virgin olive oil I used Private Reserve Greek olive oil
  • Kosher salt
  • Black pepper
  • 1 teaspoon ground cinnamon
  • ½ to ¾ teaspoon ground allspice
  • 2 small red onions cut into large pieces


  • Preheat oven to 400 degrees F, and position an oven rack in the middle
  • Place the sweet potato cubes and onion pieces in a large mixing bowl. Add a generous drizzle of extra virgin olive oil (3 to 4 tablespoons) Add salt, pepper, cinnamon and allspice. Toss well to coat.
  • Transfer to a sheet pan. Spread the sweet potatoes and onions well in one single layer (do not crowd the pan.)
  • Roast for 35 to 45 minutes, tossing occasionally, until the sweet potatoes are well cooked through and charred on the edges.


  • Tip: I use a black cast iron baking pan here. The dark color helps the veggies cook well, while cast iron provides the added benefit of even, steady heat, making it easy for the veggies to char.
  • Visit our Online Shop to browse extra virgin olive oil bundles and all-natural and organic spices and more!


Calories: 196.5kcalCarbohydrates: 46.1gProtein: 3.6gFat: 0.1gSaturated Fat: 0.1gSodium: 512.5mgPotassium: 764.3mgFiber: 7gVitamin A: 32175.6IUVitamin C: 5.4mgCalcium: 72.4mgIron: 1.4mg
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This post originally appeard on The Mediterranean Dish in 2019 and has been recently updated with new information for readers' benefit.

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I'm Suzy; born and bred right on the shores of the Mediterranean. I'm all about easy, healthy recipes with big Mediterranean flavors. Three values guide my cooking: eat with the seasons; use whole foods; and above all, share! So happy you're here...
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  1. LW says:

    5 stars
    Delicious! I didn't have all spice, so I used ginger instead.

  2. Helen says:

    5 stars
    Made this as a side dish for Thanksgiving. Very delicious. I did char roast a bit too long. The potatoes and onion were very dark and yet it was still good. Definitely a keeper recipe.

  3. Sam says:

    Hi - can you make this recipe 1-2 days before then reheat?

    1. Summer Miller says:

      Hi, Sam! I'm Summer and I work here at The Mediterranean Dish. You can absolutely make these a day or two before then just reheat them when you get to where you're going! Enjoy!

  4. Deborah Hogeboom says:

    5 stars
    These are the best! I've never been a fan of the sweetened sweet potatoes. These fit the bill and make a wonderful side dish for that Thanksgiving or Christmas dinner.

  5. Annette Davis says:

    We love this recipe! Made it this week using yams. I have always thought they were the same as sweet potatoes.
    Everyone loved them.

  6. Kate says:

    Eager to make this recipe. Just wondering if you could be more specific about size when you say large pieces of onions?

    1. Suzy Karadsheh says:

      Hi, Kate. This recipe is very forgiving. Three is no exact measurement for the size of onion here. You can just keep them in larger slices... you don't need to worry about chopping or thinly slicing them.

  7. Buddy Stonesifer says:

    5 stars
    I followed the recipe as written, threw them on the grill with turkey meatloaf. They were finished about the same time, drizzled the sweet potatoes with some honey to serve. So good!!! Definitely a keeper recipe!!!

    1. Suzy says:

      Sounds yummy! Thanks for sharing!

  8. Heather says:

    5 stars
    I made this tonight to go with eggplant parmesan. I used a butternut squash but kept everything else the same. So delicious and the house smells wonderful!! Can't wait to make these again.

    1. Suzy says:

      Wonderful! Thanks, Heahter!

    2. Donna Porro says:

      This is ridiculous—YOU DIDN’T MAKE THE RECIPE!! Please don’t comment unless you make as written! Let US make our own changes should we choose to do so!

  9. Jane says:

    5 stars
    Just made a batch of these on Sunday afternoon so I can reheat them easily throughout the week. I often pair roasted sweet potatoes with a veggie omelette for breakfast and this recipe caught my attention as a change from my normal roasted sweet potatoes. I snuck a few bites to try them when I was putting them into containers. SO very tasty. I'm so excited for my breakfasts this week! I also plan to make these for a side dish at Thanksgiving. Great recipe!

    1. Suzy says:

      Awesome! Thanks, Jane!

  10. Jacque Hastert says:

    5 stars
    What a great idea to switch up the traditional sweet potatoes on Thanksgiving! I love roasted veggies and I can't wait to start roasting these soon.