Balsamic Roasted Onions with Thyme (Vegan)
Balsamic roasted onions take the humble onion, mix it with vegan butter and balsamic vinegar, and roast it in the oven. The onions soften, with caramelized edges and a sweet-tangy glaze. The result is a sweet, tangy, deeply savory side dish that is perfect any day of the week and a holiday must-have.
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My Testing Notes
I saw this recipe on Pinterest, and I was instantly obsessed. The idea of transforming the onion from an aromatic necessity to the main event intrigued me.
The original recipe is from EatingWell, and I made a few changes. I swapped the butter for vegan butter, added Dijon mustard to balance the sweetness, and finished with a sprinkle of brown sugar before broiling.
Eat sinfully, live kindly ❤️
Ruth
Why You Will Love These Balsamic Onions
Key Ingredient Notes
Onions
You can use a yellow onion or a sweet onion. I prefer the milder flavor of the sweet onions when they are in season. Look for small to medium, similar-sized onions. I prefer the smallest size I can find.
Butter
I make this recipe vegan by using plant-based butter. You can swap vegan butter with dairy butter at equal ratios.
Balsamic Vinegar
If you are making this recipe, use your best balsamic vinegar that is comfortably affordable.
Dry White Wine
I recommend using a dry Pinot Grigio or Sauvignon Blanc. You can substitute white cooking wine or vegetable broth in equal amounts.
Brown Sugar
The original EatingWell recipe uses white sugar. I tested this with white sugar, light brown sugar, and dark brown sugar. While they were all delicious, I felt light brown sugar added a deeper color and caramelization without making the onions feel heavy. With that said, you can use any type of sugar you prefer.
See the recipe card for complete information on ingredients and quantities.
1
Prepare the onions and the vinaigrette
Start by cutting the onions from root to tip. Mix the vinaigrette. Add the dressing to the baking dish, nestle the onions in tightly, loosely cover with tin foil, and bake.
2
Oven-Roast the Onions
Flip halfway through. At the very end, sprinkle salt and brown sugar over the onions. Place them back in the oven and broil under high for 1 minute.
More side dish recipes….
My Best Roasted Balsamic Onion Tip
Keep the root ends intact. This holds the onion together; without it, the layers will come apart during cooking.
Storage and Make-Ahead Instructions
- Storage Instructions: Store leftover onions and the sauce in an airtight container in the refrigerator for up to 4 days. Reheat in the oven at 350° in a skillet over low to medium heat until the onion is warmed through.
- Make-Ahead Instructions: The flavor deepens on day 2, making these a perfect make-ahead recipe.
Perfect Pairings
How Did It Go?
I hope you loved these balsamic onions as much as I do! Before you go, please leave a rating and a comment to let me know how it went.
Balsamic Roasted Onions with Thyme (Vegan)
Equipment
- 1 9×13 rectangle baking dish
Ingredients
- 4 medium yellow onions, about 1½ pounds total
- 3 tablespoons vegan butter, melted
- 1 tablespoon olive oil
- ⅓ cup balsamic vinegar
- 2 tablespoons dry white wine, vegetable broth, or water
- 3 tablespoons light brown sugar
- ½ teaspoon Dijon mustard (optional, but recommended)
- ¼ teaspoon salt
- ⅛ teaspoon black pepper
- fresh thyme leaves, for serving
Instructions
- Before you start: Heat the oven to 425°F.
- Prepare the sauce: In a small bowl or directly in your rectangular baking dish, mix the melted butter, oil, vinegar, wine, Dijon mustard, brown sugar, salt, and pepper.
- Prepare the onions: Peel the onions, leaving the ends attached. Halve lengthwise, leaving the stem and root intact. Place in the baking dish, cut side up. Loosely cover with foil; bake for 30 minutes.
- Flip the onions: Uncover and gently turn cut-side down. Bake another 20 to 25 minutes, until tender and the sauce thickens.
- Caramelize: Remove the dish from the oven. Turn the onions cut-side up and sprinkle each half with salt and ½ teaspoon light brown sugar. Broil on low for 1 to 2 minutes, watching closely, until the sugar bubbles and the edges brown.
- Serve: Serve cut-side up with sauce and thyme.