01 - Preheat the oven to 400°F.
02 - Heat olive oil in a large skillet over medium heat. Sauté onions and garlic for 2–3 minutes until fragrant.
03 - Add chicken pieces and cook for 5–6 minutes until browned but not fully cooked through.
04 - Add mushrooms and broccoli, and sauté another 3–4 minutes. Remove from heat.
05 - In a saucepan, combine heavy cream, chicken broth, cream cheese, dried thyme, salt, and pepper. Heat gently, stirring, until smooth.
06 - Stir in mozzarella and parmesan cheese until melted and sauce thickens, about 2–3 minutes.
07 - Combine chicken-vegetable mix with creamy sauce in a large mixing bowl.
08 - Transfer the mixture to a greased casserole dish. Top with the optional shredded mozzarella.
09 - Bake for 20–25 minutes until bubbly and golden on top.
10 - Garnish with fresh parsley before serving.