Comfort Food Mashed Potato Casserole

A warm, bubbly, cheesy casserole is just what we all need for colder nights ahead. This mashed potato casserole is the pinnacle of comfort food. It's rich, creamy, cheesy, and topped with crispy bacon and fried onions. So, if mashed potatoes are already a favorite in your house, this baked version takes them to the next level. With its fluffy interior, golden top, and smoky bacon flavor, it’s the kind of recipe that makes everyone ask for seconds. It’s also incredibly convenient and easy to make ahead.

Need a more hands-off recipe? Try slow cooking your mashed potatoes.

Why You’ll Love This Mashed Potato Casserole

This dish checks every box when it comes to comfort food. Aside from being rich and creamy from the combination of butter, sour cream, and cream cheese, the mashed potatoes are smooth and fluffy, and the baked layer of melted cheddar cheese adds that irresistible gooeyness we all love. Add smoky bacon and a sprinkle of crispy fried onions on top, and you’ve got something unforgettable.

Unlike regular mashed potatoes that need to be made right before serving, this casserole can be prepared ahead of time, stored in the fridge, and baked when you’re ready. That makes it a lifesaver during the holidays or busy weeknights when you want something homemade but don’t have time for last-minute cooking.

Watch The How-To Video

Jump to:

• Why You’ll Love This Mashed Potato Casserole
• Watch The How-To Video
• Making a Balanced Mashed Potato Casserole
• Step-By-Step Overview
• Tips for Perfect Mashed Potato Casserole
• Make-Ahead Instructions
• Entrées to Serve with Mashed Potato Casserole
• How to Reheat Leftovers
• Storing and Freezing
• The Secret to Extra Creamy Mashed Potatoes
• More Side Dishes To Love
• Printable Recipe

Making a Balanced Mashed Potato Casserole

This casserole is creamy without being heavy, cheesy without being greasy, and flavorful without being overwhelming. Each bite has the perfect combination of buttery mashed potatoes, melted cheese, crispy bacon, and crunchy onions.

The addition of cream cheese and sour cream is what gives the potatoes their luxurious texture. They stay creamy and smooth even after baking, never dry or chalky. Using a mix of cheeses like cheddar, parmesan, or even Gruyère adds depth and richness, while the bacon brings smoky, savory contrast.

A few simple touches, like draining the potatoes really well and finishing the top under the broiler for a minute or two make all the difference. The result is a casserole that’s silky inside and perfectly golden on top.

Step-By-Step Overview

1. Cook the potatoes. Peel, cube, and boil them with a bay leaf until fork-tender. Drain thoroughly. This step is key so your casserole doesn’t turn out watery.
   
2. Mash them up. Return hot potatoes to the pot, add butter, sour cream, cream cheese, milk, and seasonings. Mash until smooth and creamy. Note: You can use a hand mixer for this part if you like smooth mashed potatoes. Just be sure not to overmix, as this makes the potatoes gummy.
   
3. Add the good stuff. Stir in half the bacon, half the cheddar, and all the parmesan.
4. Assemble the casserole. Spread the potatoes in a greased casserole dish. Sprinkle the rest of the bacon and cheddar over the top.
   
5. Bake until bubbly. Pop it in the oven until hot and melted, then finish with fried onions and green onions for that perfect crunch.

That’s it. The smell that fills your kitchen as it bakes is reason enough to make this recipe all season long.

Tips for Perfect Mashed Potato Casserole

• Drain your potatoes completely. This prevents the casserole from becoming watery.
  
• Use full-fat dairy. Whole milk, real butter, and full-fat sour cream give the richest flavor.
  
• Shred your own cheese. Pre-shredded cheese often contains anti-caking agents that keep it from melting smoothly.
  
• Season generously. Potatoes need plenty of salt to bring out their flavor. Taste and adjust before baking.
  
• Go for texture. The contrast of creamy potatoes and crispy toppings is what makes this dish so good. Don’t skip the fried onions or green onions on top.

Make-Ahead Instructions

This casserole is perfect for prepping in advance. Assemble it a day before you need it, but don’t add the toppings yet. Cover it tightly and refrigerate. When you’re ready to bake, uncover and add about 10 extra minutes to the cooking time. Once it’s hot and bubbly, finish with crispy onions and green onions just before serving.

You can also make and freeze it. Let the mashed potatoes cool completely, transfer to a freezer-safe dish, and wrap tightly. Thaw overnight in the refrigerator before baking. It reheats beautifully and tastes just as good as fresh.

Entrées to Serve with Mashed Potato Casserole

Mashed potato casserole pairs beautifully with so many main dishes. It’s hearty enough for holidays, but simple enough for Sunday dinners. Try serving it alongside:

• Roast turkey or chicken
• Brown sugar glazed ham
• Pot roast or brisket
• Meatloaf or grilled steak
• Baked salmon or pork tenderloin

To balance its richness, add a light vegetable side like green beans, honey roasted carrots, or a crisp salad with vinaigrette. That little bit of freshness makes every bite of casserole even more satisfying.

How to Reheat Leftovers

Reheat leftover mashed potato casserole in the oven at 350°F until warmed through, about 20 minutes. If it’s a little dry, add a splash of milk before baking. You can also microwave individual servings in 30-second intervals, stirring halfway through.

Leftovers make an excellent breakfast, too. Warm a scoop in a skillet and top it with a fried egg for the most satisfying breakfast!

Storing and Freezing

• Refrigerate: Store covered in the fridge for up to 4 days.
• Freeze: Wrap tightly and freeze for up to 2 months.
• Reheat: Thaw in the refrigerator and bake until heated through.

This casserole is a great option for meal prep or as a freezer-friendly dish to gift to a friend or family member.

The Secret to Extra Creamy Mashed Potatoes

The trick to achieving the best mashed potato casserole starts before it even hits the oven. When boiling your potatoes, make sure to start them in cold water and cook until they’re just fork-tender. Overcooking can lead to waterlogged potatoes, and undercooking makes them lumpy. Drain them completely, then return them to the warm pot for a minute or two to let the steam escape. That keeps the texture light and fluffy.

From there, add your butter first so it melts into the hot potatoes, coating every bite with flavor. Then add your sour cream, cream cheese, and milk. Mashing them with a potato masher or hand mixer while the potatoes are still warm helps everything blend together smoothly and gives you that signature creaminess this casserole is known for.

More Side Dishes To Love

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Printable Recipe