Grilled Asparagus & Red Onions with Olive Oil and Balsamic Vinegar

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Grilled asparagus and grilled red onions marry beautifully when tossed with a little balsamic vinegar and sugar.

Asparagus red onion 1

Sometimes the whole is greater than the sum of its parts. Grilled asparagus and grilled red onions are both perfectly fine dishes on their own – simple, delicious accompaniments to just about anything – but together they’re even better. The distinct green flavor of the slightly charred asparagus marries beautifully with mildly sweet caramelized red onions and, as you can see, it’s as pretty as food can be.

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For the asparagus, simply toss the spears with olive oil, salt, and pepper and cook directly on the grill. For best results, buy medium or thick asparagus. They’ll brown nicely and maintain a tender-crisp bite.

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The red onions are prepared much the same way: thick slices are coated with olive oil, salt, and pepper and then grilled to tender, sweet perfection. They take a bit longer to cook but have patience, the payoff in flavor is worth it.

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To put it all together, cut the grilled asparagus into bite-sized pieces, toss with the grilled red onions and brighten the flavors with a little balsamic vinegar and sugar.

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Delicious, healthy, and you gotta love the colors. Enjoy!

Asparagus red onion

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Grilled Asparagus & Red Onions with Olive Oil and Balsamic Vinegar

Grilled asparagus and grilled red onions marry beautifully when tossed with a little balsamic vinegar and sugar.

Servings: 4


  • 2 medium red onions, peeled
  • 1½ pounds asparagus (about 24 medium stalks), ends trimmed
  • 4 tablespoons extra virgin olive oil
  • Kosher salt
  • Freshly ground black pepper
  • ½ teaspoon sugar
  • 1 tablespoon balsamic vinegar
  • Disposable grill pan (see note)


  1. Preheat the grill to high.
  2. Prepare the red onions: Cut onions in half from root to tip, then cut the halves into ½-inch slices. Pull the slices apart and place them into a disposable grill pan. Toss with 2 tablespoons olive oil, ½ teaspoon kosher salt and ¼ teaspoon pepper.
  3. Prepare the asparagus: Place the spears in a baking dish and toss with 2 tablespoons olive oil, ¼ teaspoon kosher salt and ¼ teaspoon pepper.
  4. Place the pan of onions on the grill, along with the asparagus spears (be sure to place spears perpendicular to grates so they don't fall through). Set the asparagus dish next to the grill (do not clean). Cover and cook the vegetables for 2-3 minutes. Open the cover and, using tongs, turn the asparagus. Cover and cook 1 -2 minutes more, until the asparagus spears are nicely browned and tender-crisp. Remove the asparagus from the grill and place back in the baking dish. Stir the onions, cover, and continue cooking for about 15 - 25 minutes, stirring every few minutes, until tender and caramelized. In the meantime, transfer the asparagus spears to a cutting board and cut into 1½-inch pieces. Place back in the baking dish and toss with finished grilled onions. Add the sugar and balsamic vinegar and toss well. Taste and adjust the seasoning if necessary (I usually add a good ¼ teaspoon more salt). Transfer to serving platter and serve hot or room temperature.
  5. Note: Make your own disposable grill pan. Shape two layers of heavy duty aluminum foil over a 9 x 13-inch baking dish. Remove foil from pan.

Nutrition Information

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  • Per serving (4 servings)
  • Calories: 181
  • Fat: 14 g
  • Saturated fat: 2 g
  • Carbohydrates: 13 g
  • Sugar: 7 g
  • Fiber: 5 g
  • Protein: 4 g
  • Sodium: 477 mg
  • Cholesterol: 0 mg

This website is written and produced for informational purposes only. I am not a certified nutritionist and the nutritional data on this site has not been evaluated or approved by a nutritionist or the Food and Drug Administration. Nutritional information is offered as a courtesy and should not be construed as a guarantee. The data is calculated through an online nutritional calculator, Although I do my best to provide accurate nutritional information, these figures should be considered estimates only. Varying factors such as product types or brands purchased, natural fluctuations in fresh produce, and the way ingredients are processed change the effective nutritional information in any given recipe. Furthermore, different online calculators provide different results depending on their own nutrition fact sources and algorithms. To obtain the most accurate nutritional information in a given recipe, you should calculate the nutritional information with the actual ingredients used in your recipe, using your preferred nutrition calculator.

Gluten-Free Adaptable Note

To the best of my knowledge, all of the ingredients used in this recipe are gluten-free or widely available in gluten-free versions. There is hidden gluten in many foods; if you're following a gluten-free diet or cooking for someone with gluten allergies, always read the labels of your ingredients to verify that they are gluten-free.

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  • This recipe is a hidden gem! It’s simple to prepare, but incredibly tasty. I find that it’s great for hosting since it can be served room temperature and tastes just as good hot off the grill or having sat at room temp for a little while. I also hadn’t grilled asparagus before trying this recipe and am so pleased by how easy and tasty it is. Thanks Jenn!

    • — Chelsea on June 7, 2024
    • Reply
  • I am eating low carb and had some green beans and wanted to make your Green Beans with lemon and pine nuts, but my green beans went bad 🙁 But I had asparagus, so of course the first thing I did was go to your website to see how I could make it. I didn’t have feta, or a grill, but decided to combine this recipe with your asparagus salad with eggs (roasted the asparagus and onions instead of grilling, tossed with a little lemon juice, lemon zest and balsamic vinegar (yes, it DOES bring the dish to another level!) topped with soft boiled eggs. OH YUM! Your flavor combinations are always spot on!

    • — Heather D on July 22, 2022
    • Reply
  • This recipe turned out very well. I ate it with grilled hotdogs on the bun and parsley potatoes. It was so delicious, though, I decided to add it to my Father’s Day menu for the family. Menu: Best Grilled Chicken, Tabbouleh, Grill Asparagus and Red Onions, and watermelon cubes. Thank you!

  • Hi Jenn, I’m looking forward to trying out this dish but I only have an oven to work with, as we don’t have a grill. I’m a bit embarrassed to admit I’ve never cooked asparagus before! Can I ask how long would you broil the asparagus, would you do 2-3 minutes on each side? And broil the onions for 15-20 minutes? Thanks so much for your help!

    • Hi Mel, for the asparagus, yes, I would broil them for 2 to 3 minutes on each side (just keep an eye on them as it depends on how thick they are). And I would actually roast the onions at 400° for about 20 minutes, tossing them once halfway through. Hope that helps and that you enjoy!

      • Thanks Jenn, these instructions worked perfectly, had this as a quick, healthy and tasty side dish to baked salmon tonight. Enjoyed by all!

        • So glad it came out well — thanks for taking the time to follow up! 🙂

  • I made this asparagus dish to accompany sesame topped grilled salmon that had been marinated in a ginger, tamari and mirin blend. In my husband’s words, it was “perfect.” The balsamic and tiny bit of sugar really raise this dish to the next level. We finished every last bit of it and will definitely be making this again.

  • Omg!! So simple and over the top. As I was preparing this dish, I actually ended up broiling the asparagus, I could not get to a grill. I followed everything else but kept thinking, What else could I do to it. It needs absolutely nothing. It’s absolutely fabulous the way it is.
    Thanks Jenn.

  • I know there have been questions about making ahead and serving at room temperature. Do you think this would work with making ahead and reheating? Maybe in the Microwave?

    • Yes, that should work, Kathy. Enjoy!

  • Can you make this the day before and serve at a party at room temp? Love your recipes! They are great!!

    • — Gretchen James-Halter
    • Reply
    • Yes Gretchen, I think that would work. (And glad you’re enjoying the recipes!)

  • If you can’t grill, what would be another good way to cook the asparagus?

    • Hi London, You can definitely broil it.

  • Making this for our Memorial Day BBQ! Your website is my go-to place for great recipes when I’m entertaining or just for the family. Thank you!

    • So nice to hear, Beth! Hope you enjoy!

  • I absolutely loved it!!!

  • Great recipe! Didn’t have the balsamic vinegar (I know it is the key of the recipe), but used red wine vinegar instead and it turned out to be an amazing dish. Thanks for sharing! Will definitely do this again.

  • I add sweet potatoes, cut small, to this for another dimension. Sooo good and your guest will be amazed at your cooking prowess.

  • This is a great way to eat asparagus. We love grilled vegetables of all kinds, and we eat asparagus weekly when it is in season. I love it with cheese sauce, but often want a more healthier version. This recipe did it for me. The sweetness of the grilled onions and balsamic vinegar added just the right touch to make it a very special side dish to any meal. We had it with grilled filet mignons topped with gorgonzola cheese. Thanks for this tasty recipe. ( I tried a small portion size of this during the winter on my panini grill, and it turned out very tasty—not like the outdoor grill, but a welcome treat on a cold winter day!)

  • Simple and easy to make…good balsamic vinegar is the key to this dish. Thank You!

  • This is mouthwatering delicious!

  • This was absolutely yummy. I didn’t have red onions, so I used vidalia, and it came out great!

    • Excellent! Only problem was it was too delicious – my husband and I were fighting over the leftovers 😉

      • — Lynnessa R Struble
      • Reply
  • Healthy and delicious!!!!! wonderful!

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