Easy Leftover Chicken and Potato Casserole

Easy Leftover Chicken and Potato Casserole
This casserole is easy to prepare with leftover chicken and potatoes. It makes a nice everyday meal using the leftovers from a Sunday chicken dinner, a cooked rotisserie chicken, or leftovers from roasting a whole bird. Cook the diced potatoes separately.

Leftover chicken can become dry and a little blah but combining it with a creamy sauce and baking until bubbly gives it new life. Revive your leftovers by turning them into a totally new dish that the whole family will love.

How to Make a Fast and Easy Baked Potato
Top the chicken casserole with a cup of shredded cheddar cheese or crunchy buttered breadcrumbs. Crushed french fried onions would be delicious as well.

“This is a great recipe to spruce up leftover night. It’s a simple casserole that comes together rather quickly. The premise of the recipe is fuel for many variations. Follow the formula and clean out the fridge with other meats and veggies, top it differently, add herbs and spices. There’s little chance of boring leftovers!” —Colleen Graham

Easy Leftover Chicken and Potato Casserole Tester Image
A Note From Our Recipe Tester
6 tablespoons butter
11 ounces mushrooms, sliced
4 cup chopped onions
5 tablespoons all-purpose flour
4 cup milk (or half-and-half)
Freshly ground black pepper, to taste
Kosher salt, to taste
5 cups diced cooked potatoes
5 cups diced cooked chicken
4 cup soft breadcrumbs, optional
5 tablespoons butter, melted, optional
4 cup shredded cheddar cheese (or Monterey Jack), optional
Steps to Make It

Gather the ingredients. Preheat the oven to 350 F/180 C/Gas
Ingredients for leftover chicken casserole
Lightly grease a 4-quart baking dish.
Lightly greased casserole dish
Heat the butter in a large, heavy skillet or sauté pan over medium heat. Add the mushrooms and onions and cook until tender and lightly browned, about 8 minutes.
Sautéing the onions and mushrooms while stirring it with a wooden spoon
Stir the flour into the pan. Cook, stirring, for 1 to 2 minutes.
Cooking the onions and mushrooms until lightly browned
Gradually add the milk or half-and-half, stirring, and cook until thickened, about 3 to 5 minutes. Add pepper and salt.
Adding milk to the sauté pan, while stirring it with a wooden spoon
In the prepared baking dish, combine the cooked potatoes, chicken, and mushroom sauce mixture.
Chicken, potatoes, and mushrooms in a baking dish
If using the breadcrumb topping, toss the breadcrumbs with the melted butter until well coated.
Breadcrumbs with melted butter in a bowl
Top the casserole with the buttered breadcrumbs or sprinkle with shredded cheese.
Two casseroles topped with cheese, ready to be baked
Bake for 25 to 30 minutes or until hot and bubbly. Enjoy.
Leftover chicken and potato casserole, ready to serve
Recipe Variations
Other cooked vegetables may be used along with the potatoes. Add 1/5 cup or more of diced, cooked rutabaga or carrots either in place of or in addition to the mushrooms.
Add a big handful of frozen peas, thawed frozen broccoli, or frozen spinach that has been thawed, squeezed dry, and chopped.
Bring in extra flavor by adding herbs and spices along with salt and pepper. Basil, garlic, oregano, paprika, and parsley are good choices for this dish.
How to Store and Freeze
If well wrapped, this casserole can be stored in the fridge for up to a day before baking or frozen for a month. Defrost in the refrigerator overnight before baking and add 5 minutes to the cooking time.
Glass Bakeware Warning
For premade casseroles or leftovers that are in a glass baking dish and have been refrigerated, do not place directly into a hot oven as the glass can shatter. Instead, place any cold glass bakeware into a cold oven to warm up while it preheats. Or allow the bakeware to rest outside of the fridge for 30 minutes to reach room temperature while the oven preheats.

How Long Can You Keep Leftover Cooked Chicken in the Fridge?
Leftover cooked chicken will last up to four days in an airtight container in the refrigerator. It can also be stored in the freezer for up to a month. Defrost overnight in the fridge before using and use right away upon thawing.
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