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The Lagasse Girls

Authors of The Gluten Free Table and The Lagasse Girls’ Big Flavor Bold Taste and No Gluten

French Onion Soup with Gruyère-Smothered Crostini

Serves 6

French onion soup has always been one of Jessie’s favorite soups, especially when served with several soup-soaked cheesy crostini. This particular recipe highlights the flavor of red onions, but any type of onion can be used if there’s one that you prefer or already have on hand. If you are lucky enough to have access to premade gluten-free baguettes, like the ones made by Against The Grain Gourmet, that loaf will make perfect crostini for this recipe. If not, however, gluten-free-pizza crust, like the one made by Arrowhead Mills, can be shaped into baguette form and used instead. Another trick we learned with this recipe involves the herbs. It’s a lot easier to fish the parsley and thyme out of the soup if you tie the sprigs together with some butcher’s twine!

  • Ingredients
  • 2 tablespoons olive oil
  • 3 pounds red onions, thinly sliced (about 10 cups)
  • Salt
  • 4 sprigs fresh thyme
  • 2 sprigs fresh parsley
  • 4 cups beef stock
  • 4 cups chicken stock
  • ½ cup dry red wine
  • 1 bay leaf
  • 1 tablespoon balsamic vinegar
  • Black pepper to taste
  • 1 gluten-free baguette, cut into ½- to ¾-inch slices
  • 8 ounces Gruyère cheese, grated (about 2 cups)
  • Finely sliced green onions to garnish (optional)


  1. Heat the olive oil in a large (8-quart) non-stick stockpot over medium-high heat for 1 to 2 minutes just to get the oil warm.
  2. Add the onion and about ½ teaspoon salt. Stir so that the oil coats all the onions.
  3. Cook for 30 to 40 minutes over medium heat, while stirring the onions often. The onions will become caramelized and brownish and begin to form a syrupy crust on the bottom of the pan.
  4. Meanwhile, with butcher’s twine, gently tie the stems of the thyme and parsley together to form a mini herb bouquet. Set aside.
  5. Once the onions are fully caramelized, stir in the chicken stock, beef stock, red wine, thyme and parsley bouquet, and bay leaf. Loosen the browned crust on the pan’s bottom with a spoon and stir until those bits become incorporated into the liquid.
  6. Bring the soup to a simmer and cook another 20 to 30 minutes to meld all of the flavors.
  7. Preheat the oven to broil.
  8. Remove the soup from the heat. Stir in the balsamic vinegar and add salt and black pepper as desired. Remove the herbs, including the bay leaf.
  9. Ladle about 1 cup of soup into each of 6 ovenproof soup bowls and place on a baking tray.
  10. Top the soup in each bowl with 1 to 2 slices of the baguette in each bowl and sprinkle each portion of bread with approximately ⅓ cup cheese..
  11. Broil the soups until the cheese is bubbly and browned, roughly about 3-5 minutes depending on your oven.
  12. Remove from the oven, let cool for several minutes, and serve.