Mashed Potato Casserole

5 from 8 votes

Mashed Potato Casserole is a rich, decadent, buttery, tangy side dish that delivers classic comfort in make-ahead form.

Prep Time45

Cook Time20

Total Time1 5

Course: Side Dish

Cuisine: American

Servings:

Calories: 517kcal

In a large pot add quartered Yukon Gold Potatoes. Cover with cold water and place on the stovetop over medium-high heat. Add ½ tsp salt and stir into water. Bring water to a boil and let potatoes cook for 18-22 minutes (depending on the size of your cut potatoes). Potatoes are done when you can easily pierce with a fork.
5 pound Yukon Gold Potatoes, Cold water to cover potatoes, ½ teaspoon salt
Drain potatoes and place them in a large mixing bowl. Using a hand mixer with beaters, break the potatoes up in the bowl. Add 1 stick of softened butter, garlic powder, ground white pepper, and salt. Mix with a hand mixer for 30 seconds on high.
1 stick salted butter, ½ teaspoon garlic powder, ½ teaspoon ground white pepper, 1½ teaspoon salt
Add sour cream, warmed milk, and ½ of the cheddar cheese to the bowl. Beat on high until no lumps remain in potatoes.
½ cup sour cream, ½ cup whole milk, 3 cups cheddar cheese
Lightly grease a 9x13 baking dish and preheat the oven to 375 degrees F. Add potato mixture to the baking dish. Top with remaining cheddar cheese. Place in the oven and bake for 20 minutes, or until cheese is fully melted.
3 cups cheddar cheese
Sprinkle cooked bacon and chives on the top of the casserole. Serve and enjoy.
10 strips bacon, Chives

Storage:

To Store: Store leftover baked mashed potato casserole in an airtight container in the refrigerator for up to 4 days.
To Freeze: You can freeze the leftover casserole in an airtight container or freezer bag for up to 1 month. Defrost in the refrigerator before reheating.
To Reheat: I like to reheat individual servings in the microwave, covered with a damp paper towel, so the casserole does not dry out.

Tips:

Make sure not to overmix your potatoes. They will become gluey and tough if they are mixed for too long.

The purpose of warming the milk is so that you don’t bring down the potatoes' temperature when mixing.

It’s best to let the sour cream sit out while the potatoes are cooking so that it can come up to room temperature before adding it to your hot potatoes.

You can make this dish ahead of time and then when you’re ready to eat it, pop it back into the oven to heat it up!