Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Pat the chicken breast dry with a paper towel and cut it into 1-inch bite-sized cubes.
Clean the cremini mushrooms with a damp cloth and slice them into halves.
In a small bowl, whisk together the melted ghee, minced garlic, sea salt, and black pepper.
Place the chicken cubes and mushroom halves on the prepared baking sheet and drizzle the garlic-ghee mixture over them, tossing to coat thoroughly.
Spread the ingredients into a single layer and roast for 18 to 20 minutes until the chicken is cooked through and the mushrooms are golden.
While the tray roasts, gently warm the pre-cooked quinoa in a small saucepan over low heat.
Remove the baking sheet from the oven, squeeze fresh lemon juice over the mixture, and garnish with freshly chopped parsley.
Portion the fluffy quinoa into a bowl and top with the roasted garlic butter mushrooms and chicken.