Savory Casseroles

Mashed Potato Casserole

Boil 'em, mash 'em...mix 'em with cheesy goodness and call it a mashed potato casserole.

For the first 14 years of my life, I didn’t know this was a casserole. In my mind, it was just mashed potatoes. I couldn’t figure out why my grandmother’s mashed potatoes — while still delicious — just didn’t taste the same. All things became clear when I helped my mom make this mashed potato casserole one Thanksgiving. Does it just consist of only mashed potatoes and butter? Oh no. Throw in a heaping helping of cheddar, sour cream, and cream cheese to turn already tasty potatoes into this masterpiece.

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If you’re looking for other recipes for your Thanksgiving or Christmas table, I highly recommend you try this sweet potato casserole, or – one of my proudest recipe developments – a lighter take on a green bean casserole.

A dollop of mashed potato casserole sprinkled with melted shreds of cheese sits on a white plate.


As you might expect, the ingredients for this mashed potato casserole are relatively straightforward. This recipe does not require any flour, making it safe for friends with gluten-free diets.

  • 5 pounds potatoes
  • ½ cup butter (1 stick)
  • 1 cup sour cream
  • 8 ounces cream cheese (1 block)
  • 1 teaspoon garlic salt
  • ¼ cup milk
  • 1 cup cheddar cheese, shredded plus more for sprinkling on top

How to make mashed potato casserole

Start by peeling and dicing five pounds of potatoes. While you can cut your potatoes into whatever size you prefer, the smaller you dice your potatoes, the faster they will cook. Throw on your favorite Netflix show or podcast – this takes a while, but the final product is worth the tedium.

Next, place your potatoes in a large stockpot and cover with water. Bring this to a rolling boil, allowing to simmer for 5-10 minutes, or until your potatoes are fork tender. Once your potatoes are tender, carefully drain them. (If you want to be an overachiever, you can save the potato water for thickening your homemade pasta sauce or watering your plants — but that’s definitely “extra”.)

Place your drained potatoes in a large bowl. I like to use my KitchenAid stand mixer for this step, but a hand mixer would also work well. If you are using a KitchenAid and you happen to have one of the 5-quart glass bowls in addition to the standard stainless steel bowl, I highly recommend using the larger option. If using the standard stainless steel, you will probably need to split your ingredients in half and make this in two batches, as all of the potatoes do not quite fit into the standard bowl.

Place your stick of butter in the midst of your potatoes, allowing the heat from the potatoes to melt the butter. While the butter is melting, add your sour cream, cream cheese, garlic salt, milk, and shredded cheddar. Mix thoroughly, until all ingredients are well incorporated. The longer you mix, the more mashed your potatoes will be — if you prefer some potato chunks, stop mixing as soon as things look incorporated.

Once you have a uniform mass of potatoes that are mashed to your liking, pour them into a greased casserole dish and preheat your oven to 350 degrees F. This recipe makes one 9″ by 13″ pan, but it can also be split into multiple smaller dishes. I recently purchased a set of 9″ by 6″ meal prep tins, and poured half of my potatoes into each dish. We ate one pan of potatoes for dinner, but the other went in the freezer — either to use at our Thanksgiving, or to share with a friend from church. If you elect to freeze this recipe I recommend sealing the pan as best you can with wax paper and plastic wrap in order to mitigate freezer burn.

Bake your potatoes for 35-40 minutes. If you would like some extra cheesiness, sprinkle additional shredded cheddar atop the ‘taters when they have 10 minutes left in the oven. If you are making these potatoes from frozen, make sure they have thawed completely (and you have removed all wax paper/plastic wrap!) before baking.

Allow these potatoes to cool briefly before serving. At most of our family celebrations, these are the first dish to enter the “clean plate club”. But, if you happen to have leftovers, they can easily transform into wonderful potato pancakes the next day.

Mashed Potato Casserole

Classic mashed potatoes are brought to new heights with the addition of cheese, sour cream, and cream cheese.
Prep Time 40 minutes
Cook Time 40 minutes
Total Time 1 hour 20 minutes
Course Side Dish
Cuisine American
Servings 20 servings


  • 5 pounds potatoes
  • ½ cup butter (1 stick)
  • 1 cup sour cream
  • 8 ounces cream cheese (1 block)
  • 1 teaspoon garlic salt
  • ¼ cup milk
  • 1 cup cheddar cheese, shredded plus more for sprinkling on top


  • Peel and dice potatoes. Boil until tender (5-10 minutes) and then drain.
  • Place potatoes in a large bowl. Add stick of butter, covering with steaming potatoes, and allow butter to melt.
  • Once butter has melted, add sour cream, cream cheese, milk, garlic salt, and cheddar cheese. Mix thoroughly, either by hand or using a mixer.
  • Pour into a greased casserole dish. Bake at 350 degrees F for 35-40 minutes. If desired, sprinkle the casserole with additional shredded cheese during the last 10 minutes of baking.
  • Serve hot. Enjoy!


I highly recommend mashing these potatoes using a mixer. If using a Kitchen-Aid stand mixer and not a hand mixer, be aware that this amount of potatoes will cause your standard stainless steel mixer to overflow. In order to mitigate this mess, I recommend either (a) splitting the potato mashing into two batches, or (b) using the larger 5-quart glass bowl, if you have it available.
This recipe freezes well! If freezing, place into a greased casserole dish or aluminum pan before baking your fully-mixed potatoes. Seal well, with foil and plastic wrap. Thaw your potatoes completely before baking.

2 comments on “Mashed Potato Casserole

  1. Pingback: Sweet Potato Casserole - Whisk Averse Baking

  2. Pingback: Gluten Free Green Bean Casserole - Whisk Averse Baking

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