Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Clean the cremini mushrooms and halve any that are particularly large; slice the chicken breast into 1-inch bite-sized cubes.
In a small glass bowl, whisk together the melted ghee, minced garlic, chopped thyme, and chopped rosemary.
Place the chicken cubes, mushrooms, and trimmed asparagus spears onto the prepared baking sheet in a single layer.
Drizzle the garlic-herb ghee mixture over the chicken and vegetables, tossing thoroughly to ensure everything is evenly coated.
Sprinkle the sea salt and black pepper over the tray.
Roast in the center of the oven for 18-20 minutes, or until the chicken is cooked through and the mushrooms are tender and browned.
Remove from the oven and drizzle with fresh lemon juice before serving immediately.