Heat oven to 350° F. In a large nonstick skillet, cook the turkey until it is no longer pink. Add the gravy mix and 1 cup water. Stir frequently until the sauce comes to a boil; cook 1 minute. Lightly coat a 9-inch square baking dish or four 16-ounce baking dishes with vegetable cooking spray. Spoon in the turkey. Top with the peas, then the mashed potatoes. Sprinkle with the Pecorino Romano. Bake 20 minutes or until heated through and the top is golden.