In a bowl, add the chicken thighs, salt, pepper, garlic, dried parsley, and olive oil, and toss until evenly coated.
2. Step
Add the chicken to a skillet on medium-high heat. Sear until golden brown, about 4 minutes. Flip and cook the other side of the chicken, 2 minutes. Remove the chicken from the pan and set aside.
3. Step
Preheat oven to broil.
4. Step
Add the butter, sliced onions, salt, and pepper to the same pan, stirring occasionally until softened. Reduce heat to low and cook until they are deeply caramelized, about 1 hour.
5. Step
Add thyme and beef broth and bring the mixture to a simmer.
6. Step
Add the chicken on top of the onions, and sprinkle with Gruyère cheese.
7. Step
Broil for 5 minutes, until the cheese is melted and golden brown.
