This is like French Onion Soup, but better. I didn’t think it was possible to top the original, but this does. Balsamic makes everything a bit better. This soup is a little on the sweeter side than traditional onion soup, but the balsamic vinegar and tamari help balance that out. I also thought that the addition of the mustard made the flavor really interesting as well. The other great thing about this recipe is that it is a lot less work and a lot faster than making traditional French Onion Soup. The only thing I didn’t really like was the swiss cheese. It was a little bland. I think Gruyère might be an improvement or a really sharp white cheddar would be even better.
Caramelized Balsamic-Red Onion Soup With Cheese-Topped Croutons
Adapted from Serious Eats
- 1/4 cup olive oil
- 1 tablespoon butter
- 6 large red onions, thinly sliced
- 2 teaspoons salt
- 1/4 cup balsamic vinegar
- 2 tablespoons low-sodium gluten free tamari or soy sauce
- 2 tablespoons prepared mustard
- 6 cups low-sodium vegetable broth
- 1/8 teaspoon freshly ground black pepper
- 6 slices of bread (I used a gluten-free baguette from Whole Foods)
- 3/4 cup grated Swiss cheese
- Heat a large pot over medium heat for one minute. Add the oil and swirl to coat the bottom of the pan, and then add the butter. Once it melts, add the sliced onions and salt, and then reduce heat to medium-low. Cook, stirring occasionally, until the onions turn golden brown, about 30 minutes.
- Add the balsamic vinegar, soy sauce, and mustard, stir well, and cook for five minutes.
- Pour in the broth, and turn the heat to high. When it comes to a boil, reduce the heat to low, partially cover, and simmer for 15 minutes.
- Meanwhile, preheat the oven to 350°F. Place the slices of bread on a baking sheet covered with aluminum foil. Transfer the baking sheet to the oven and cook for five minutes. Carefully remove the sheet, and turn on the broiler. Divide the cheese between the slices of bread. Set the sheet under the broiler for however long it takes to melt the cheese, about 30 seconds. Remove the sheet, turn off the heat, and set aside.
- Season the soup with black pepper and, if needed, more salt. Ladle the soup into bowls and top with a crouton. Serve immediately.