Split muffins; scoop out center, leaving a 1/2-inch shell. Place muffin shells on a baking sheet, and bake at 350° for 8 minutes or until lightly browned.
Combine turkey, gravy, onion, and parsley in a medium saucepan; cook over medium heat 15 minutes. Spoon turkey mixture into muffin shells; garnish with parsley, if desired.
Note: For well-seasoned gravy, use any prepared gravy mix or Roast Fowl Gravy