Roasted onions are soft and sweet, making them perfect for serving alongside roasted veggies or meats. We bake whole onions with butter and herbs and then roast them until super soft and unbelievably delicious!
Adam was the first to suggest testing whole roasted onions, and I am so happy that he did! I was initially skeptical, but these sweet, soft, roasted onions have become one of my favorite holiday recipes. They are stunning on the table and taste incredible.
I can’t wait for you to try this easy recipe. For more onion recipes, see our roasted onion dip and my absolute favorite French onion soup (really, it’s so good!).
Key Ingredients
- Onions: I love using small to medium yellow or sweet onions for this recipe. When they are available, I love Walla Walla or Vidalia onions!
- Butter: I bake my onions with butter, making them so delicious. Salted butter is perfect, but unsalted is perfectly fine! Plant-based butter works in this recipe.
- Herbs: To make our roasted onions super flavorful, I add lots of chopped fresh herbs like thyme, rosemary, and sage. If you can find them, look for the poultry herb packet, which usually has all three inside. You can use dried herbs for these baked onions; I included tips in the recipe below.
- Vinegar: This is optional, but I love drizzling the onions with thick balsamic vinegar before serving.
How to Make Roasted Onions
You can roast onions with their skins on (like roasted garlic). However, I like to take a few extra steps to make this extra special.
First, trim both ends of the onions, but leave the skins intact. Trimming the top allows our butter and herbs to seep down into the center of the onions while trimming the bottom helps them stay put in the baking dish.
Next, season generously with salt and broil the onions briefly. This technique, borrowed from making homemade pho, chars the tops of the onions in their skins, adding a delightful toasty flavor and a beautiful caramelized color.
Then I add a bit of butter and a variety of herbs. I love bay leaves, rosemary, thyme, and sage, which complement the roasted onions beautifully. Finally, I roast the onions covered, which allows them to steam a bit and makes them extra soft and sweet.
These are lovely with roasted chicken and are a staple on our Thanksgiving table next to our herb roasted turkey. They are especially good with a drizzle of turkey gravy.
Enjoy these roasted onions alongside mashed potatoes, mushroom stuffing, and roasted butternut squash. Or blend them into soups to make them sweet and creamy. I especially love these blended into our roasted cauliflower soup and this butternut squash soup.
Butter Roasted Onions
- PREP
- COOK
- TOTAL
These incredible roasted onions are soft and sweet and perfect for serving alongside other roasted vegetables or meats. For serving, we love adding a drizzle of balsamic or sherry vinegar over the onions.
Watch Us Make the Recipe
You Will Need
6 small to medium onions, skins left on with top and bottom trimmed
3 tablespoons (42g) butter, cut into 6 thin slabs
1/2 teaspoon fine sea salt
1/2 teaspoon cracked black pepper
1 to 2 tablespoons chopped fresh herbs like thyme, rosemary, or sage
3 bay leaves
Good quality balsamic vinegar, balsamic glaze, or sherry vinegar, optional
Finishing salt like Maldon flaked salt, optional
Directions
1Season the top and bottom cut ends of each onion with salt. Arrange the onions in an oven-safe baking dish.
2Slide the onions underneath the broiler and broil until the tops are golden brown and some onion skin chars.
3Turn the oven to bake and heat to 400°F (204°C).
4Remove the baking dish from the oven and place a slab of butter on top of each onion. Then, mound the herbs onto the butter so that they will fall into and over each onion when the butter melts.
5Season with pepper and scatter the bay leaves around the onions.
6Cover the baking dish with foil or tuck baking parchment paper into the corners to cover the dish well.
7Bake the onions until very soft and sweet, 60 to 90 minutes. Serve as is or with a drizzle of vinegar and a pinch of finishing salt over the top.
Adam and Joanne's Tips
- Vegan: Use a plant-based butter or use olive oil.
- The nutrition facts provided below are estimates.
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One taste of the butter roasted onions and bingonthey are in rotation. We grew our own and have several dozen exactly the right size. Used cultured butter and our garden sage. Cut two heads of orgsnic garlic heads in half, drizzled olive oil and popped them into the casserole once the onions were browned. Covered, 40 minutes exactly as specified. Thank you. Can’t wait to make them again.
OH MY GOD another winner! These onions are silky smooth, soft and delicious! I’ve tried 4 of your recipes in the past week, and every one has been an absolute winner taste and ease-wise. Thank you!
Wondering if this recipe works with pearl onions as well?
Hi Julie, pearl onions would be great! The roasting time might be a bit less.
These sound great! Can they be made in advance??
Hi Laura, You can make these up to four days in advance.
in the oven now…hope it is as good as it looks…
Thank you for the whole roasted onion recipe. I’ve use this twice now, and I absolutely love it. Currently, I’m trying to prepare meals from a wheelchair (temporarily). This is one of those quick and easy and healthy solutions to meal preparation. Love your site. Thank you for sharing Inspired Taste with the masses. To your audience: please be sure to add the balsamic vinegar at the end; this one little step brings out and enhances the sweetness of the onion.
Yummy
Very easy recipe, very delicious roasted onions. Will be making hummus next. Thank you so much.
While looking at the recipe for roasted onions I was delighted to see that you mentioned using a sprinkling of Maldon Salt I was born and lived just a few miles from Maldon and still love to go there when in England. It is very famous for the salt produced there. And it is a very lovely place to visit. Thank you
this is just the kind of recipe i LOVE! will be making soon. thank you so much!!
Thanks so much! Will make tonight.