Baked Loaded Mashed Potato Casserole

Loaded Mashed Potato Casserole turns 4 cups of leftover mashed potatoes into a cheesy, bacon-filled side dish with sour cream, two kinds of onion and a buttery cheese-cracker topping. It’s a great second act for Thanksgiving leftovers, but there’s no reason to save it just for the holidays.

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“This recipe is a winner! Easy to improvise if needed. I made it yesterday and it turned out to be melt in your mouth, delicious and memorable. Absolutely perfect way to use up leftovers!”

Melinda

“Made this on Sunday before Christmas for our family Christmas meal. This was a huge hit! This recipe is now added to my favorites recipes.”

Debra

“This is KILLER GOOD!! Took to a football party as a side. I felt bad . . . my dish went before the main one and other sides!!!”

Patty

Four Cups Of Leftover Mashed Potatoes, One Loaded Casserole

Thanksgiving is one of my favorite holidays, but with a gathering of just five people, we often have plenty of leftovers afterward. I usually can’t resist making a double batch of mashed potatoes for the holiday, and this casserole is my favorite way to put the extra potatoes to work. Of course, you could just reheat them with Homemade Gravy, but the bacon, cheddar and crunchy cracker topping make a strong argument for trying something different.

The trick is to stir sour cream into the potatoes before folding in sharp cheddar, bacon, red onion, green onion and parsley. Then the whole thing goes into the oven under a buttery layer of crushed cheese crackers. You get creamy potatoes underneath and a crunchy, cheesy topping on top.

It uses 4 cups of mashed potatoes and serves six, so it’s a handy option after Thanksgiving dinner, at Christmas or as a side for a football party. A half batch works if your leftover supply is a little smaller.

Loaded Mashed Potato Casserole Ingredients

A full recipe card, including exact ingredient amounts, appears at the bottom of this post.

• nonstick cooking spray – keeps the baked casserole from sticking to the dish.
• mashed potatoes – use 4 cups of already-cooked potatoes, whether they’re leftovers from Thanksgiving or a fresh batch. My Mashed Potatoes With Heavy Cream work well here, but the recipe doesn’t require a particular style of mash.
• sour cream – a dollop of sour cream adds tang and makes refrigerated potatoes easier to stir and creamy again after baking.
• garlic powder and black pepper – season the potatoes without adding extra chopping. Taste your mashed potatoes before deciding whether they need any additional salt.
• sharp cheddar cheese – adds lots of cheesy flavor. Some goes inside, and a little is reserved for the top. Other cheeses like mozzarella or Parmesan work here, but will change the flavor a bit.
• bacon – six cooked, crumbled slices give the casserole its loaded-potato flavor. I make Bacon In The Oven when I need a batch for recipes like this.
• red onion – a little finely chopped onion adds savory contrast to all the dairy and cheese. White or yellow onions are also great here.
• green onion or chives – adds a fresher onion flavor and some color.
• fresh parsley – brightens up the mixture visually and adds an herby note.
• cheese crackers – coarsely crush Cheez-Its or Goldfish for the crunchy topping. Leave a few larger pieces for texture.
• unsalted butter – coats the crushed crackers so the topping browns as the casserole bakes.

How To Make Loaded Mashed Potato Casserole

1. PREP. Heat the oven to 350 degrees F, grease a large casserole dish and toss the crushed cheese crackers with melted butter.

2. SOFTEN AND SEASON. If the mashed potatoes are cold, microwave them for 60 to 90 seconds, just until soft enough to stir. Mix in the sour cream, garlic powder and black pepper.

3. FOLD IN THE EXTRAS. Reserve 2 tablespoons each of bacon and cheddar. Fold the rest into the potatoes along with the red onion, green onions and parsley.

4. SPREAD. Transfer the potato mixture to the prepared baking pan and smooth it into an even layer with a spatula.

5. TOP. Scatter the buttery cracker crumbs and reserved bacon and cheddar over the potatoes.

6. BAKE. Bake for 25 to 30 minutes, or until the casserole is heated all the way through and golden brown on top. If using leftovers, check for 165 degrees F in the center.

Loaded Mashed Potato Casserole Variations

• CHANGE THE CRUNCH – Substitute crushed Ritz crackers or potato chips for the cheese crackers if that’s what you have on hand.
• SKIP THE BACON – Leave out the bacon for a meatless version. The cheddar, onions and cracker topping still give the potatoes plenty of flavor.
• MAKE A HALF BATCH – Have only 2 cups of leftover mashed potatoes? Halve the ingredients and use a smaller baking dish; begin checking sooner for doneness.

Make Ahead, Storage And Reheating

• Make Ahead: If using freshly made mashed potatoes, assemble the casserole up to 2 days before baking. Cover tightly and refrigerate, then uncover and let stand for 30 minutes before baking. It may need a little extra oven time. If using leftover mashed potatoes, remember that the original 3- to 4-day refrigerated storage window still applies, including the time before and after baking.
• Refrigerate: For casserole made with fresh mashed potatoes, refrigerate leftovers promptly in shallow containers, uncovered until fully chilled, then cover and use within 3 days. For casserole made with leftover mashed potatoes, keep the original 3- to 4-day refrigerated leftover window in mind rather than starting a new clock.
• Reheat: Cover individual portions and warm in a 350 degree F oven, or cover and microwave, until the center reaches 165 degrees F. The crackers may soften after reheating, but the potato mixture will still be creamy.
• Freeze: Freeze cooled portions in airtight containers for up to 3 months. Thaw in the refrigerator and reheat thoroughly. Freezing may soften the potato texture and cracker topping.