Preheat your oven to 400°F (200°C).
Mince the garlic cloves and slice the cremini mushrooms into halves or thick quarters.
In a small bowl, melt the ghee and whisk in the minced garlic, dried thyme, sea salt, and black pepper.
Place the chicken breast, mushrooms, and broccoli florets onto a large parchment-lined sheet pan.
Drizzle the garlic ghee mixture over the chicken and vegetables, tossing them thoroughly to ensure everything is evenly coated.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the mushrooms are golden and tender.
Remove from the oven, squeeze fresh lemon juice over the entire pan, and garnish with chopped fresh parsley before serving.