French Onion Soup

rate this recipe:
5 from 5 votes
Prep Time: 10 mins
Cook Time: 1 hr 30 mins
Total Time: 1 hr 40 mins
Serves 4 to 6
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Ingredients

  • 6 tablespoons extra-virgin olive oil
  • 3 pounds medium yellow onions, halved and thinly sliced
  • ¾ teaspoon sea salt
  • tablespoons balsamic vinegar
  • tablespoons tamari
  • tablespoons fresh thyme leaves
  • 3 garlic cloves, minced
  • 3 tablespoons all-purpose white flour
  • 1 cup dry white wine
  • 6 cups vegetable broth
  • Freshly ground black pepper

Topping

  • Baguette slices
  • Gruyère cheese, aged cheddar, and/or Parmesan cheese
  • Fresh thyme
  • Pinch of red pepper flakes, optional

Instructions

  • Heat the oil in a large pot over medium heat. Add the onions, salt, and several grinds of pepper and toss to combine. Reduce the heat to low and cook for about 40 minutes, stirring every few minutes, or until the onions are very soft. Increase the heat to medium and cook 15 to 20 more minutes, stirring often, until golden brown. Add the vinegar, tamari, thyme, and garlic and stir. Sprinkle the flour on the onions, stir, and cook for 2 minutes. Stir in the wine and cook 2 minutes, or until evaporated. Add the broth and simmer over medium heat for 30 minutes.
  • Preheat the oven to 450°F and line a baking sheet with parchment paper. Place the baguette slices, topped with cheese, on the baking sheet and bake until the slices are toasted and the cheese is melted, 8 to 10 minutes.
  • Ladle the soup into ramekins or bowls and top each with a toasted baguette piece, fresh thyme, and a pinch of red pepper flakes, if desired.