- Calories:600 kcal
- Protein:35 g
- Carbohydrates:180 mg
- Sugar:12 mg
- Salt:1 g
- Energy:2514 kJ
- Fat:40 g
-
1Gather the Ingredients
Gather all your ingredients to make the chicken and potato casserole.
-
2Preheat the Oven
Preheat the oven to 350°F (180°C or Gas Mark 4). Lightly grease a 2-quart baking dish.
-
3Sauté the Vegetables
In a large skillet, heat 3 tablespoons of unsalted butter over medium heat. Add 8 ounces of sliced mushrooms and 1 cup of chopped onions, cooking until tender and lightly browned, about 8 minutes.
-
4Add Flour
Sprinkle 2 tablespoons of all-purpose flour into the skillet and cook, stirring occasionally, for 1 to 2 minutes.
-
5Add Milk
Gradually stir in 1 cup of milk or half-and-half and cook until thickened, about 3 to 5 minutes. Season with freshly ground black pepper and kosher salt to taste.
-
6Combine Ingredients
In the prepared baking dish, mix together 2 cups of diced cooked potatoes, 2 cups of diced cooked chicken, and the mushroom sauce mixture.
-
7Prepare Breadcrumb Topping
If you’re adding a breadcrumb topping, toss 1 cup of soft breadcrumbs with 2 tablespoons of melted unsalted butter until evenly coated.
-
8Top and Bake
Top the casserole with the buttered breadcrumbs or sprinkle with 1 cup of shredded cheddar cheese, if desired. Bake for 25 to 30 minutes, or until hot and bubbly.
- Turning leftovers into a delicious casserole saves time and reduces waste in the kitchen.
- Try enhancing the flavor by adding herbs or spices like basil, garlic, or parsley.
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 rotisserie chicken, or a roasted whole bird. The potatoes can be leftover roasted potatoes or, if you need to cook them separately, simply steam them until tender.

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.
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 new dish that the whole family will love.
How to Adapt This Recipe
There are a thousand little ways to vary this recipe and amp up the flavor. Add leftover cooked veggies, like steamed broccoli, or throw in a handful of mixed frozen vegetables or frozen peas. If you like your casseroles extra saucy, double the flour and milk in the mushroom sauce. Add herbs like thyme to the sauce or the breadcrumb topping. Or swap the cheddar cheese for whatever melty cheese you have lying around—you can even mix and match if you only have little nubbins of different cheeses. Crushed French-fried onions mixed into the topping would be delicious as well.
What to Serve With Chicken and Potato Casserole
Casseroles are rich and hearty, so they are best paired with something fresh and green. A simple side salad goes with everything, but you can also serve this dish with sautéed greens, broccoli, or asparagus. Roasted acorn squash is another delicious way to get in some veggies.
Tips for Making the Best Chicken and Potato Casserole
- No baking dish, no problem - If you don't have a small baking dish, you can bake this casserole in the same skillet you use to sauté the mushrooms and make the white sauce. Just make sure that your skillet is oven-safe.
- How to prevent clumps - When adding the milk or half-and-half to the mushroom mixture, add it slowly, stirring the whole time. This prevents lumps from forming in the sauce.
- Taste test - Because all the ingredients in this casserole are cooked, you can taste the mixture before baking to make sure it has enough seasoning.
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.
Feeling Adventurous? Try This:
- Add more veggies - Other cooked vegetables may be used along with the potatoes. Add 1/2 cup or more of diced, cooked rutabaga or carrots either in place of or in addition to the mushrooms. More options you can add are a big handful of frozen peas, thawed frozen broccoli, or frozen spinach that has been thawed, squeezed dry, and chopped.
- Add more flavor - 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.











