Add the butter to a saucepan and melt it over medium heat.
Add in the diced vegetables and sauté until the carrots are al dente.
Add in the cream of chicken soup and leftover turkey and mix together.
Allow it to begin to simmer.
Remove it from the heat.
Stir in the peas.
Place the mixture into a casserole dish.
Top with leftover mashed potatoes.
Bake in the oven for about 20 minutes or until the mixture is bubbling.
Optional: broil for 2-3 minutes to make the potatoes crispy.
Top with parsley and serve hot.
Video
Notes
Chicken substitute: Rotisserie chicken, baked chicken thighs, or any cooked chicken substitutes 1:1 for turkey.Canned soup shortcut: Replace the homemade sauce with 2 cans of condensed cream of chicken soup thinned with about ½ cup of broth.Vegetable swaps: Frozen mixed vegetables, green beans, broccoli, or leftover roasted vegetables all work in place of or in addition to the fresh vegetables.Mashed potato topping: Warm to room temperature before spreading. Add a splash of milk and stir if still stiff from the fridge.Stuffing topping alternative: Leftover stuffing can replace the mashed potato topping for a different but equally delicious result.Make-ahead: Assemble and refrigerate covered for up to 24 hours. Add 5 to 10 minutes to bake time if going in cold.Storage: Refrigerator, covered, up to 3 to 4 days. Freezer (unbaked), up to 3 months. Thaw overnight in fridge before baking.Reheating: Oven: cover with foil, 350º F for 20 to 25 minutes. Microwave: with a splash of broth, in 30-second intervals.