3 c not mashed potatoes
1 c shredded cheddar cheese
1 can fried onions
1½ c shredded, cooked turkey
1 package frozen mixed peas & carrots (10 oz)
1 can cream of chicken soup
½ c milk
½ tsp dry mustard
¼ tsp garlic powder
¼ tsp white pepper

Combine potatoes, ½ c cheese, and ½ c fried onions. Spoon into a greased 1½-quart casserole dish. Spread across bottom and up sides of dish.
Combine next 7 ingredients (turkey through pepper). Pour into potato shell. Bake uncovered at 375° for 30 minutes. Top with remaining cheese and onions. Bake for additional 5-10 minutes.
Let stand 10-15 minutes before serving.