Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Clean the mushrooms with a damp cloth to remove debris and slice them in half; finely mince the garlic cloves and chop the fresh thyme.
Cut the chicken breast into uniform 1-inch bite-sized cubes to ensure even cooking and faster roasting.
In a large mixing bowl, whisk together the melted ghee, extra virgin olive oil, minced garlic, thyme, sea salt, and black pepper.
Add the chicken cubes and halved mushrooms to the bowl, tossing thoroughly until every piece is well-coated in the garlic-butter mixture.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is enough space between pieces to allow for proper browning rather than steaming.
Roast for 18-22 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the mushrooms are golden and tender.
Remove from the oven, drizzle with fresh lemon juice for brightness, and garnish with chopped fresh parsley before serving immediately.