Roasted Onions in tangy rosemary dressing is a go-to dish that’s ready in under an hour. Scrumptious, caramelized baked onions are easy to make with this recipe!!
Explore different ways to use this layered root vegetable — it’s the foundation of many delicious sauces and can be enjoyed as a more prominent addition to your meal.
Tender and sweet, these baked onions are caramelized to perfection and boast rich flavor from a homemade Dijon dressing.
Fresh sprigs of rosemary and bright lemon juice help round out the flavors, making this simple roasted onions recipe one that you’ll want to keep!
Roasted Red Onions Tips and Tricks
- Use fresh herbs. You can often substitute dried rosemary when making recipes, but for oven roasted onions, fresh sprigs make all the difference.
Be sure to remove the stems and chop the leaves to help release their flavor and aroma!
- Tip to avoid teary eyes: There have been numerous tricks shared throughout the years, from wearing goggles to slicing near running water.
The newest tip for cutting onions is to hold a chunk of bread or a cracker in your mouth, letting it hang out as you chop.
I can’t guarantee it will work, but it’s worth a try!
- Get your hands dirty! You can use spoons to toss the dressing into the vegetables, but honestly, hands really are the best tool for the job.
How To Cut An Onion Into Wedges
First, trim both the root and stem sides of the onion.
You’ll often see dried brown roots on one side — slice off enough to remove these, but leave the thick white nub intact. This prevents the layers from separating.
- Peel and slice.
Remove the peel and the outer layer (or two) if it appears dented or damaged. Slice in half through the stem, then in half again to make quarters.
Kitchen Tools You Will Need
- Rimmed Baking Sheet – Used for anything from cookies to roasting, a good baking pan will last for years.
- Quality Knives and a big solid Cutting Board make prepping a breeze and are well worth the investment.
- Citrus Juicer – This gets every last drop out, which makes juicing lemons so much easier.
Roasted Onions FAQ
This easy roasted red onions recipe pairs wonderfully with meat and poultry dishes. Enjoy with a simple weeknight dinner, or add it to your holiday menu, doubling as needed for extra guests.
It’s especially delicious alongside a beef roast, pork tenderloin, or any main course that could use a tangy and sweet side dish.
The general rule for onion varieties is this: red is the best raw, white is used to flavor dishes, and yellow is the most versatile for cooking.
That said, there are always exceptions to the rule. When paired with herbs like rosemary or parsley, the sharp flavor of red onion is muted, and it caramelizes perfectly in this roasted onions recipe!
Baking the onions is my recommendation! If you need to use them quickly to prevent spoiling, dice and freeze them for up to 3 months! Then you can use toss them into soups or skillet meals whenever you want to.
Or, make a pint’s worth of caramelized onions in a crockpot.
With love, from our simple kitchen to yours.
Other Easy Vegetable Recipes
Rosemary Roasted Onions + Video
- 2 medium red onions
- 1 medium sweet yellow onion
- 1/4 cup extra virgin olive oil
- 1 lemon, juiced
- 1 teaspoon Dijon mustard
- 3 cloves garlic, minced
- 2 sprigs fresh rosemary, stems removed and chopped
- 1 teaspoon kosher salt
- 1/2 teaspoon freshly ground black pepper
- Preheat oven to 400° F.
- Trim onion both the root and stem sides of the onion. Be sure to leave the root intact (cut so that the dried brown roots are cut off and only a white nub remains).
- Peel onions. Place onion with the cut side down on a cutting board and cut into wedges.
- Place onions onto a baking pan. Set aside.
- In a medium bowl, combine olive oil, lemon juice, mustard, garlic, rosemary, salt and pepper. Whisk until well combined.
- Pour the dressing over the onions and toss well. You can use spoons, but I think hands are the perfect tool for this job.
- Bake onions for 30 to 45 minutes, until tender and browned. Toss the onions once during cooking.
- Remove from the oven, toss again, and transfer to a serving bowl.
- Serve and enjoy!
All nutritional information is based on third party calculations and is only an estimate. Each recipe’s nutritional value will vary depending on the ingredients used, measuring methods, and portion sizes.
Originally published August 2011, updated and republished January 2023
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