Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast into one-inch cubes and halve the cremini mushrooms, ensuring they are uniform in size for even cooking.
In a large mixing bowl, whisk together the melted ghee, minced garlic, sea salt, and black pepper until well combined.
Add the chicken cubes and halved mushrooms to the bowl, tossing thoroughly until every piece is evenly coated in the garlic-ghee mixture.
Spread the chicken and mushrooms in a single layer on the prepared baking sheet, leaving space between pieces to ensure they roast rather than steam.
Roast in the center of the oven for 18 to 20 minutes, or until the chicken is cooked through and the mushrooms are golden brown and tender.
Remove from the oven and immediately drizzle with fresh lemon juice and sprinkle with the chopped fresh parsley.
Serve the roasted chicken and mushrooms over a bed of warm cooked quinoa to soak up the flavorful garlic butter juices.