Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Slice the chicken breast into uniform 1-inch cubes and clean the mushrooms, halving any that are particularly large.
In a small microwave-safe bowl, melt the ghee and whisk in the minced garlic, fresh thyme, sea salt, and black pepper.
Place the chicken and mushrooms in a large mixing bowl and pour the garlic-herb ghee over them, tossing until every piece is well-coated.
Spread the chicken and mushrooms in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Roast in the oven for 18 to 20 minutes, or until the chicken is cooked through and the mushrooms have developed a deep golden-brown color.
Remove from the oven and immediately toss with fresh lemon juice and chopped parsley.
Divide the warm cooked quinoa between plates and top with the roasted garlic butter mushrooms and chicken.