Mashed Potato Casserole is a creamy potato dish baked in the oven and topped with cheese. It’s made with potatoes, milk, butter, sour cream, thyme, salt, and cheese all combined in a baking dish and served with your favorite meal. Since this can be baked while you finish cooking the rest of your dinner, you can have everything ready to eat at the same time.
What is Mashed Potato Casserole?
This mashed potato casserole recipe is loaded with flavor from butter, fresh thyme leaves, and cheese. It’s a vegetarian side dish that can be served with dinner or brought to a potluck or holiday party. You’ll love how easy it is to make and your family will love the old-fashioned, comforting flavors.
- 8 cups potatoes, peeled and chopped: Russet potatoes are best for mashing and baking in this casserole.
- 3⁄4 cup milk: Use whole milk for the best texture.
- 3 tablespoon butter: Unsalted butter allows you to control the amount of salt that’s added to the dish.
- 1⁄4 cup sour cream: Full-fat sour cream makes this dish even creamier.
- 2 thyme sprigs: Fresh thyme leaves are the most flavorful, but you can use dried thyme if you don’t have fresh leaves.
- 1 teaspoon salt: Kosher salt is best to use when cooking or baking.
- 1 cup cheese, shredded: Shredded cheddar cheese can be bought in the dairy section of the grocery store or you can buy a block of cheese and grate it yourself.
How to make mashed potato casserole:
Here’s a brief overview of how to make this dish. See the recipe card below for the specific recipe instructions.
1. Preheat the oven to 350F.
2. Boil potatoes in salted water until soft.
3. Heat up the milk with thyme and butter. Remove thyme leaves after the milk boils up.
4. Mash potatoes with aromatic milk and season with salt to taste.
5. Spoon potato into a baking dish and top with cheese.
6. Bake at 180C/350F for 30-35 minutes.
Tips for success:
Here are a few tips for success and variations you can try to make this the best mashed potato casserole you've ever had.
- Top with marshmallows, pecans, walnuts, pumpkin seeds, or fried onion strings for a crunchy, balancing texture.
- You can use other types of cream in this dish. Try cream cheese, milk, heavy cream, or half and half.
Can I make this casserole for dinner?
You can add some ingredients to turn this simple dish into a complete dinner. Try adding ground beef, chicken, ham, or turkey.
Don’t forget the veggies. Some options include green beans, broccoli, cauliflower, asparagus, or mushrooms.
Can I make the potatoes a different way?
If you want to try a different version of this casserole without mashing the potatoes, there are other options. You can use sweet potatoes, diced Yukon golds, or tater tots for a different texture or flavor.
What other kinds of cheese can I use?
This recipe uses shredded cheddar cheese but you can use mozzarella, parmesan, swiss, Colby jack, Monterey jack, pepper jack, gruyere, or Havarti. They each have a different taste and will make your dish unique and interesting.
How to store:
Store any leftover casserole in an airtight container in the refrigerator for up to five days. Reheat it in the microwave with 30-second increments until it’s hot all the way through.
To freeze the entire casserole, wrap it in aluminum foil and plastic wrap. Label it with what it is, how to cook, and the date. Labeling will help you remember later. Remember that if you cook it from frozen, it will take longer to cook in the oven without thawing first. Keep the foil on until the last 30 minutes of cooking so the top can brown.
How can I make this casserole ahead of time?
This is the perfect make-ahead dish. You can make it up until just before baking and then wrap it tightly and freeze or refrigerate.
What can I serve mashed potato casserole with?
Serve your casserole with meatloaf, pork chops, grilled chicken breast, crunchy salad, fruit salad, pepper-crusted steak, or crusty bread.
Can I make this dish in an instant pot?
Yes, you can definitely make mashed potato casserole in a pressure cooker. Follow the instructions and pour the mixture into the bowl of the instant pot. Seal the lid, set to high pressure for 10 minutes, allow the pressure to release naturally for five minutes. Remove the lid and serve hot.
- 8 cups potatoes, peeled and chopped
- 3⁄4 cup milk
- 3 tablespoon butter
- 1⁄4 cup sour cream
- 2 thyme sprigs
- 1 teaspoon salt
- 1 cup cheese, shredded
- Preheat the oven to 350F.
- Boil potatoes in salted water until soft.
- Heat up the milk with thyme and butter. Remove thyme leaves after the milk boils up.
- Mash potatoes with aromatic milk and season with salt to taste.
- Spoon potato into a baking dish and top with cheese.
- Bake for 30-35 minutes.
Amount Per Serving: Calories: 367Total Fat: 15gSaturated Fat: 9gTrans Fat: 1gUnsaturated Fat: 5gCholesterol: 42mgSodium: 596mgCarbohydrates: 49gFiber: 5gSugar: 5gProtein: 11g