1Heat oven to 350°F. Spray 2-quart casserole with cooking spray; set aside. Make mashed potatoes as directed on pouch using water, milk and butter.
2In 2-quart saucepan, heat turkey, vegetables, gravy and poultry seasoning to boiling over medium-high heat, stirring occasionally. Pour turkey mixture into casserole. Spoon or pipe potatoes around edge of casserole.
3Bake uncovered 35 to 40 minutes or until mixture bubbles around edge of casserole.