Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Pat the chicken breast dry with paper towels and cut into 1-inch bite-sized cubes.
Wipe the cremini mushrooms clean with a damp cloth and slice them into halves or quarters depending on their size.
In a small bowl, whisk together the melted ghee, extra virgin olive oil, minced garlic, sea salt, black pepper, and red pepper flakes.
Place the chicken cubes and mushrooms onto the prepared baking sheet and drizzle the garlic-ghee mixture over the top.
Toss the ingredients thoroughly with your hands or a spatula to ensure every piece is evenly coated, then spread into a single layer.
Roast in the center of the oven for 18-22 minutes, or until the chicken is cooked through and the mushrooms are golden brown and tender.
Remove from the oven, squeeze the fresh lemon juice over the tray, and garnish with finely chopped fresh parsley before serving.