Caramelized Balsamic Red Onion Soup with Cheese-Topped Croutons Blossom Lady Jul 20, 2020 08:09 AM Try this sweeter, simpler take on traditional French onion soup, topped with toasted cheese croutons. You can use any kind of mustard—Dijon, spicy brown, or even plain old yellow. Make the croutons while the soup is simmering, so everything can be ready at about the same time. Ingredients ¼ cup olive oil 1 tablespoon butter (optional) 6 large red onions (4 to 5 pounds), thinly sliced 2 teaspoons salt ¼ cup balsamic vinegar 2 tablespoons soy sauce 2 tablespoons prepared mustard 6 cups water... onion soup, french cuisine, summer recipe, healthy, blossomkitchen Like!1 Add to bookmarksAssign tags