Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Slice the chicken breast into bite-sized pieces and slice the cremini mushrooms into thick segments.
Toss the chicken and mushrooms on the baking sheet with half of the melted ghee, sea salt, and black pepper.
Spread the mixture in a single layer and roast for 15-18 minutes until the chicken is cooked through and the mushrooms are golden.
While roasting, mince the garlic and sauté it in the remaining ghee in a large skillet over medium heat for 1 minute until fragrant.
Add the cooked quinoa and fresh spinach to the skillet, stirring for 2 minutes until the spinach is just wilted.
Remove the roasted chicken and mushrooms from the oven and transfer them into the skillet with the garlic butter mixture.
Toss everything together to coat evenly, garnish with fresh chopped parsley, and serve immediately.