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Mashed Potato Casserole in a white baking dish

Mashed Potato Casserole

Mashed Potato Casserole is a delicious side dish recipe that is made with either freshly made mashed potatoes, or leftover mashed potatoes. It's tasty and creamy!
5 from 1 vote
Course: Side Dish
Cuisine: American
Keyword: leftover mashed potatoes, potato side dish
Prep Time: 15 minutes
Cook Time: 45 minutes
Total Time: 1 hour
Servings: 8
Calories: 448kcal
Author: Sandy


  • Mixing Bowl
  • 8"x8" Baking Dish
  • Foil


  • 4 cups Mashed Potatoes* (leftovers are great for this) Recipe in Notes
  • ¾ cup Sour Cream
  • ¾ cup Milk
  • 4 oz Chives, chopped (about 5 Tablespoons), divided
  • ½ teaspoon Garlic Powder (optional)
  • ½ teaspoon Salt (or to taste)
  • ½ teaspoon Pepper
  • 1 ¾ cups Shredded Cheese, divided
  • ½ cup Cooked Chopped Bacon


  • Heat oven to 350° F. Spray a 8"x8" baking dish with cooking spray.
  • In a large mixing bowl, add the mashed potatoes, sour cream, milk, 1 cup of the shredded cheese, 3/4 of the chives, salt, and pepper. Mix well.
  • Add the mashed potato mixture to the baking dish and lightly pat down with a spoon or spatula. Cover with foil and bake for 25 minutes.
  • Take out of oven after 25 minutes and remove foil. Sprinkle on the remaining 3/4 cup of cheese, the bacon pieces, and the remaining chives. put back into the oven, uncovered, and bake for another 20 minutes or until the cheese is melted and the potatoes are bubbling.
  • Serve hot.


*Mashed Potatoes Recipe


  • 2 1/2 pounds Potatoes, cut in cubes
  • 1 teaspoon Salt
  • 2 cloves Garlic, smashed
  • 6 Tablespoons Butter
  • 3/4 cup Warm Milk
  • 1/4 teaspoon Black Pepper


  • Cut potatoes into small cubes and add to large pot with 1/2 teaspoon of the salt, garlic, and cold water that just covers potatoes. Bring to boil, then reduce to a low boil and cook until fork tender. It will take about 15 minutes.
  • Drain the water and add butter, remaining salt, black pepper, and milk. Use a potato masher to blend the mixture until a smooth and creamy texture forms. Adjust salt if needed.


Calories: 448kcal