Preheat the oven broiler. LIne a baking sheet with aluminum foil and coat lightly with cooking spray. In a bowl, mix together the Parmesan, butter, mayonnaise, lemon juice and seasonings. Set aside. Place tilapia fillets on the lined baking sheet and broil for 3 minutes. Carefully turn the fillets and continue broiling another 3 minutes. Remove the tilapia from the oven and coat the top of each fillet with the creamy cheese mixture. Broil for 2 additional minutes or until the topping is browned and fish flakes easily with a fork.