These balsamic onions are such a simple yet delicious side to any dish. I recently made these for Thanksgiving when an instacart delivery left me with two extra bags of red onions. Needless to say they were a huge hit as They pair well with the traditional flavors of thanksgiving dinner.

These are absolutely perfect for the holidays. They are so easy to make and almost impossible to mess up. I highly recommend these for any experience level.


If you decide to give these onions a try, be sure to tag me in your posts so that I can see all of your delicious creations.



onions of all colors

Which onions are best for this recipe? Red. Hands down, red onions have the most bite, but when cooked they have so much natural sugar that they get caramelized within the tissues of the onion. Unlike white and yellow onions, which lose flavor when cooked, the red onion’s flavor becomes enhanced.

Yellow and white onions are also incredible however. If you want to use these colors instead, replace the balsamic in this recipe with beef stock and top with asiago cheese for roasted french onion halves. 

the perfect balsamic balance

Balsamic vinegar has a very bold and distinct flavor. To balance out the harshness of the vinegar, we will add two parts olive oil to one part balsamic.

When it comes to seasonings in this recipe, feel free to get creative. I decided to add rosemary, parsley, black pepper and truffle salt.

It is important to not over-season the onions as they provide a very rich flavor by themselves. Treat seasonings as an enhancement. You want to elevate the natural flavor of the onion rather than burying the caramelized taste.



Onions are almost 100% water. The parts that aren’t water are fibrous and therefore count as carbs. Balsamic also adds carbs with very little protein or fat. However, the olive oil contributes to making this recipe almost equal parts fat and carbs.

  • Protien 3% 3%
  • Carbs 23% 23%
  • Fat 29% 29%


  • 1/2 cup extra virgin olive oil
  • 1/4 cup balsamic vinegar
  • 1 tablespoon dried rosemary
  • 1/2 tablespoon dried parsley
  • salt and pepper to taste
  • 8 red onion



Step by Step Instructions

Step 1

Start by cutting the root off of the onion. Then, using the cut as a stable base, slice the onion in half vertically. Peel and rinse your halved onions.

Step 2

Preheat the oven to 400 degrees Farenheit. Place the onion halves face down in a glass baking tray at least 3 inches deep.

Step 3

Pour the olive oil and balsamic over the onions. Season lightly with salt, pepper, parsley and rosemary.

Step 4

Bake uncovered at 400 degrees for 50 minutes to 1 hour.

Step 5

Let cool and enjoy!