Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with paper towels and cut into 1-inch bite-sized pieces.
Clean the cremini mushrooms with a damp cloth and slice them into halves or quarters depending on their size.
In a small bowl, whisk together the melted grass-fed ghee, extra virgin olive oil, minced garlic, fresh thyme, sea salt, and black pepper.
Place the chicken and mushrooms on the prepared baking sheet and pour the garlic-ghee mixture over them, tossing thoroughly to ensure every piece is well-coated.
Spread the mixture into a single layer and roast for 18 to 20 minutes, or until the chicken is cooked through and the mushrooms are beautifully caramelized.
Remove from the oven and immediately toss with fresh chopped parsley.
Serve the hot roasted chicken and mushrooms over a bed of fresh baby spinach, allowing the heat to slightly wilt the greens.