Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Slice the chicken breast into bite-sized strips and halve the cremini mushrooms.
In a large mixing bowl, combine the chicken and mushrooms with melted ghee, minced garlic, sea salt, black pepper, and fresh thyme leaves.
Toss everything together until the chicken and mushrooms are thoroughly coated in the garlic-ghee mixture.
Spread the mixture in a single, even layer on the prepared baking sheet to ensure everything roasts evenly.
Roast in the oven for 18 to 20 minutes, or until the chicken is cooked through and the mushrooms are tender and golden brown.
While the tray roasts, gently warm the pre-cooked quinoa in a small saucepan or the microwave.
Remove the baking sheet from the oven and immediately drizzle the chicken and mushrooms with fresh lemon juice.
Divide the warm quinoa between serving bowls and top with the roasted garlic butter mushroom and chicken mixture.
Garnish with freshly chopped parsley and serve immediately while hot.