
extra-virgin olive oil, divided
large onion, halved and thinly sliced
freshly chopped thyme
Kosher salt
Freshly ground black pepper
cloves garlic, minced
boneless skinless chicken breasts, cut into 1" pieces
dried oregano
all-purpose flour
low-sodium beef broth
shredded Gruyère
Freshly chopped parsley, for garnish (optional)
In a large skillet over medium heat, heat 2 tablespoons oil. Add onions and season with salt, pepper, and thyme. Reduce heat to medium-low and cook, stirring occasionally until onions are caramelized and jammy, about 25 minutes. Stir in garlic and cook until fragrant, 1 minute more. Turn off heat and remove onion mixture. Wipe skillet clean. In a large bowl, season chicken with salt, pepper and oregano, then toss with flour. Heat remaining oil in same skillet over medium-high heat. Add chicken and cook until golden on all sides and mostly cooked through, about 8 minutes. Add beef broth and return caramelized onions to skillet. Bring mixture to a boil, then reduce heat and simmer until chicken is cooked through and beef broth reduces slightly, about 10 more minutes. Add Gruyère and cover skillet with a lid. Cook until cheese is melty, about 2 minutes. Remove from heat and garnish with parsley before serving.