01 -
Melt 4 tablespoons butter in a large heavy pot over medium heat. Add sliced onions, dried thyme, bay leaves, 1 1/2 teaspoons kosher salt, and black pepper. Cook, stirring frequently and scraping the bottom, until onions are tender and deep amber, approximately 35 to 45 minutes.
02 -
While onions cook, peel and slice carrots, cut celery, and mince garlic. Set aside.
03 -
Add the remaining 2 tablespoons butter to the pot. Once melted, stir in carrots, celery, and garlic. Cook occasionally stirring until vegetables are crisp-tender and vibrant, about 5 minutes.
04 -
Season chicken breasts or thighs evenly with remaining 1 teaspoon kosher salt. Butterfly thick breasts as needed for uniform cooking.
05 -
Pour white wine and dry sherry into the pot. Stir occasionally and cook until mostly evaporated, about 2 to 3 minutes.
06 -
Sprinkle flour evenly over the mixture and cook, stirring constantly, for 1 minute to remove raw flavor.
07 -
Gradually pour in chicken broth while stirring. Add chicken in a single layer and bring to a lively simmer on medium-high heat.
08 -
Reduce heat to maintain a gentle simmer. Stir and scrape the bottom occasionally. Cook until chicken reaches an internal temperature of 165°F, approximately 10 minutes for thighs or 12 to 20 minutes for breasts.
09 -
Position oven rack 3 to 4 inches from broiler. Place baguette slices topped with Gruyère on a rimmed baking sheet and broil until cheese melts and bubbles, about 30 seconds to 1 minute.
10 -
Transfer chicken to a board and shred with forks. Return shredded chicken to pot, remove bay leaves, and adjust seasoning to taste.
11 -
Ladle soup into bowls, topping each with a cheesy toast slice if desired. Serve hot for a comforting meal.