Today’s Mashed Potato Casserole is the ultimate creamy, cheesy potato side dish! It’s a Merkley favorite and one we make for so many holidays.

It’s loaded with sour cream, cream cheese, cheddar, parmesan and bacon. Yes, all the best things in one delicious dish! It has all the flavors of loaded mashed potatoes baked into an easy 9×13 casserole, which means we love making it for Thanksgiving, Christmas, Easter, Sunday dinners, and potlucks.

With so many great ingredients, it’s not only delicious but feeds a crowd and can be prepped ahead, making it one of our favorites to prep for the holidays.

For more favorite potato sides, be sure to check out our Funeral Potatoes, Twice Baked Potato Casserole, and classic Mashed Potatoes.

Why You’ll Love It + Why it works:

  • Feeds a Crowd: Bakes in a 9×13 pan, making it perfect for holidays and potlucks.
  • Make Ahead and Save Time: Great make-ahead side dish for busy family dinners and holiday meals.
  • Cream Cheese and Sour Cream Keep it Creamy: They add richness and help the potatoes stay soft after baking.
  • Cheese and Bacon go Inside and on Top: Mixing some in and saving some for the topping gives flavor in every bite and a pretty finish.
Russet potatoes on a counter.

Mashed Potato Casserole Ingredients

  • Potatoes, peeled and cubed (5 pounds): Creates the creamy mashed potato base and make the casserole hearty.
  • Sour cream (1 cup): Adds creaminess and tang to the mashed potatoes.
  • Butter (½ cup): Adds buttery flavor and helps make the potatoes smooth.
  • Cream cheese, cubed (8 ounces): Makes the casserole extra creamy and rich. We always use full fat cream cheese.
  • Milk (½ cup): Helps loosen the potatoes and create a smooth texture.
  • Garlic salt with parsley flakes (2 teaspoons): Seasons the potatoes with garlic flavor, salt, and a little herb flavor.
  • Pepper (to taste): Adds seasoning and balances the richness.
  • Bacon, cooked, chopped, and divided (12 slices): Adds smoky flavor and a delicious topping. We prefer to make Bacon in the Oven but you can also use a microwave bacon if you’re in a rush.
  • Cheddar cheese, divided (2 cups): Melts into the potatoes and creates a cheesy topping.
  • Parmesan cheese (½ cup): Adds salty, nutty flavor and makes the potatoes even more flavorful.
  • Green onions, for garnish: Add freshness, color, and a loaded baked potato finish.

How to Make Mashed Potato Casserole

POTATOES. Peel and cube 5 pounds of potatoes. Place in a large pot and add water until just covering potatoes. Bring to boil. Once boiling, reduce to a simmer and cook for 18-20 minutes.

MASH. Drain water and mash potatoes using a potato masher or spoon (do not over-mix or potatoes will become gummy). Add 1 cup sour cream, ½ cup butter, 8 ounces cream cheese, and ½ cup milk until well combined.

SEASON. Add 1 teaspoon garlic salt, and black pepper to taste. Fold in ½ of the cooked bacon, 1 cup cheddar cheese, and ½ cup parmesan cheese. Stir well.

A baking dish covered with cheese, bacon, and green onions.

BAKE. Spoon into a lightly greased 9×13 pan. Top with remaining shredded cheddar cheese and the rest of the bacon. Bake at 350°F for 20-25 minutes.

TOPPINGS. Garnish with green onions or chives.

Kristyn’s Recipe Tips

  • Cut the potatoes into similar-size cubes so they cook evenly.
  • Drain the potatoes well before mashing so the casserole does not turn watery.
  • Add the sour cream, butter, cream cheese, and milk while the potatoes are warm so everything melts together smoothly.
  • Save half the bacon and some cheddar for the top so the casserole looks extra delicious.
  • Make-ahead tip: assemble the casserole earlier in the day or the day before, cover and refrigerate, then bake when ready, adding extra time if it starts cold.
Close up of a casserole dish of loaded mashed potato casserole topped with cheese, bacon, and green onions.
5 from 123 votes

Mashed Potato Casserole Recipe

Mashed Potato Casserole is a creamy, cheesy 9×13 side dish with sour cream, cream cheese, cheddar, parmesan, bacon, and green onions.
Servings: 12
Prep: 35 minutes
Cook: 20 minutes
Total: 55 minutes
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Ingredients 

  • 5 pounds potatoes, peeled and cubed
  • 1 cup sour cream
  • ½ cup butter
  • 8 ounces cream cheese, cubed
  • ½ cup milk
  • 2 teaspoons garlic salt (with parsley flakes)
  • pepper to taste
  • 12 slices bacon, cooked, chopped, and divided
  • 2 cups cheddar cheese, divided
  • ½ cup parmesan cheese
  • green onions, for garnish

Instructions 

  • Peel and cube potatoes.
  • Place in pot and add water until just covering potatoes. Bring to boil. Once boiling, reduce to a simmer and cook for 18-20 minutes.
  • Drain water and mash potatoes using a masher or spoon. Add sour cream, butter, cream cheese, and milk until well combined. Add salt and pepper. Fold in ½ the bacon, 1 cup cheddar cheese, and parmesan cheese. Stir well.
  • Spoon into a lightly greased 9×13 pan. Top with remaining cheddar cheese and the rest of the bacon.
  • Bake at 350°F for 20-25 minutes. Garnish with green onions and ENJOY!

Notes

    Recipe Tips.
    • Cut the potatoes into similar-size cubes so they cook evenly.
    • Drain the potatoes well before mashing so the casserole does not turn watery.
    • Add the sour cream, butter, cream cheese, and milk while the potatoes are warm so everything melts together smoothly.
    • Save half the bacon and some cheddar for the top so the casserole looks extra delicious.
    • Make-ahead tip: assemble the casserole earlier in the day or the day before, cover and refrigerate, then bake when ready, adding extra time if it starts cold.
    Make ahead of time. We recommend making this no more than 48 hours in advance, cover and refrigerate. Cook until warmed throughout. 
    Store. Store leftovers in an airtight container in the fridge for 3-5 days. 
    Freeze. To freeze, simply spread them into a freezer Ziploc bag and squeeze out as much air as possible. They’re best when used within 6-8 weeks, but can last for up to 4 months. 
    Let potatoes thaw in the fridge overnight. Place potatoes in a casserole dish and bake at 350°F for about 25 minutes. Add additional cheese and top and bake for an additional 5 minutes.

    Nutrition

    Calories: 469kcal, Carbohydrates: 25g, Protein: 15g, Fat: 34g, Saturated Fat: 18g, Cholesterol: 89mg, Sodium: 883mg, Potassium: 912mg, Fiber: 4g, Sugar: 1g, Vitamin A: 855IU, Vitamin C: 21.7mg, Calcium: 296mg, Iron: 6.5mg

    Recipe FAQ

    Make ahead of time?

    We recommend making this no more than 48 hours in advance, cover and refrigerate. Cook until warmed throughout.

    How to store?

    Store leftovers in an airtight container in the fridge for 3-5 days.

    How to freeze?

    To freeze, simply spread them into a freezer Ziploc bag and squeeze out as much air as possible. They’re best when used within 6-8 weeks, but can last for up to 4 months.
    Let potatoes thaw in the fridge overnight. Place potatoes in a casserole dish and bake at 350°F for about 25 minutes. Add additional cheese and top and bake for an additional 5 minutes.

    This recipe was first shared October, 2015.

    About Kristyn

    Kristyn Merkley is a published cookbook author, wife, mom of six, and major food enthusiast! For the past 15 years, she has been sharing foolproof, family-friendly recipes—each one tested in her kitchen—that anyone can master. As a seasoned recipe creator, she loves making cooking simple, stress-free, and totally doable for everyone!

    Get my cookbook!

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    5 from 123 votes (58 ratings without comment)

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    104 Comments

    1. Lynn says:

      Can you assemble this casserole and then freeze it?

      1. Lil' Luna Team says:

        Yes, you can assemble this casserole and freeze it before baking. Prepare the recipe through Step 4, then cover the dish tightly with plastic wrap and foil and freeze for up to 2 months.

        When ready to serve, thaw overnight in the refrigerator. Bake at 350°F for 25 to 30 minutes, or until heated through and bubbly. Add the green onions after baking.

    2. Candice h says:

      5 stars
      I’m about to make it for my works pot luck. Which cheddar cheese tastes best mild? Or sharp? Please help!

      1. Lil' Luna Team says:

        I’d go with sharp for a potluck so the cheese flavor really stands out!

    3. Alison says:

      Could I put this in a crockpot to keep it warm for a few hours?

      1. Lil' Luna Team says:

        You can transfer the casserole to a crockpot to keep it warm or skip baking in the oven and use the crockpot instead. Once the potatoes are mixed, transfer them to the crockpot, top with the remaining cheese, and heat on low until hot (about 60-90 minutes) and the cheese is melted. Then switch to warm (up to 2 hours) and add the bacon bits before serving.

    4. rita yazbeck says:

      5 stars
      Delicious recipe! I love mashed potatoes.

    5. Kathy Mischka says:

      This Mashed Potato Cassarole was awesome. Could be made with shredded chicken, turkey or almost any kind of meat. Family loved it. Could also add favorite vegetables. Endless possibilities! Thanks for the recipes.

    6. jenny B says:

      5 stars
      I made this recipe for Easter last year and it did not disappoint. Sadly I had none to take home as everyone went back for seconds.

    7. Marianne Vitaliano says:

      5 stars
      What a combination of ingredients for this casserole!

      How can you not love it?…. butter, potatoes, sour cream, cheese, cream cheese and bacon, with toppings. Steaming hot, served with your turkey, ham or roast beef and chicken? You can’t go wrong with this casserole and I can’t wait to make this for Thanksgiving!

    8. Roni says:

      5 stars
      This dish is so good, and extremely easy. Have to double this for our family. Everyone loves it. The addition of the bacon and green onions are what makes this dish a favorite.
      Make at least 4 to 5 times a year

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