Preheat your oven to 375°F (190°C). Lightly butter a 9x13 inch baking dish and set aside.
Heat 1 tablespoon of butter in a large skillet over medium heat. Add the chicken thighs and sear on both sides until golden brown, about 3-4 minutes per side. Remove and set aside.
In the same skillet, add the remaining butter and melt. Add mushrooms and cook until softened, about 5 minutes.
Stir in the garlic and thyme, cooking until fragrant, about 1 minute. Pour in the heavy cream and chicken broth, bringing to a simmer.
Return the chicken to the skillet, coating with the sauce. Transfer mixture to the prepared baking dish.
Top with Gruyere cheese and bake in the preheated oven for 20-25 minutes or until the chicken reaches an internal temperature of 165°F (74°C).
Remove from oven and let rest for 5 minutes before serving.
Notes
For a deeper flavor, marinate the chicken in advance using your favorite herbs and spices. This dish also pairs well with a side of roast potatoes or a fresh garden salad.