Looking for a leftover mashed potato recipe? This Loaded Mashed Potato Bake casserole is the most delicious way to use up leftover mashed potatoes. It’s loaded with bacon, cheese and sour cream!

Closeup of loaded mashed potato bake casserole with wooden spoon in it.

Thanksgiving is one of my favorite holidays, but with a gathering of just six people, we’re often stuck with quite a bit of Thanksgiving recipes leftovers after the big meal, especially when it comes to turkey and mashed potatoes.

After the holiday, I make cranberry sauce muffins from the remaining cranberry sauce, and then leftover turkey breast chili and leftover turkey wontons from the bird.

Leftover ham from a baked ham with pineapple sauce becomes ham and potato soup.

I’m prepared for the fact that even the smallest turkey or whole ham feeds way more than six people, but for some reason, I find it impossible to make a small batch of mashed potatoes.

Even when I limit it to one small potato per person, somehow once they’re all mashed up, I have enough to serve an army.

Then the question becomes, what to do with leftover mashed potatoes?

While you can simply reheat leftover mashed potatoes, use them on top of mini shepherd’s pie, or even make mashed potato cakes or mashed potato croquettes, my favorite way to serve leftover mashed potatoes a second time is this Loaded Mashed Potato Bake.

Closeup of potato, bacon and cheese casserole with wooden spoon inserted into center.

How long are leftover mashed potatoes good for in the fridge?

As long as they are refrigerated promptly (no more than 2 hours after serving) and covered tightly, mashed potatoes will last about 3 or 4 days.

How do you reheat mashed potatoes?

My favorite way (and the easiest!) is to make baked mashed potatoes by simply placing them in a casserole dish, covering it with foil, and baking at 350 degrees F until they are completely heated through.

But why not add some extra flavor before you reheat? That’s where this Loaded Mashed Potato Bake recipe comes in.

Tips for making this leftover mashed potato recipe successful:

This recipe works great with leftover mashed potatoes (or even leftover blue cheese mashed potatoes), but you can also make it starting with fresh mashed potatoes (i.e. make mashed potatoes specifically in order to make this recipe).

If using leftover mashed potatoes, the potatoes do need to be slightly warmed before stirring in the other ingredients.

Cold mashed potatoes are very hard to stir and incorporate with the other ingredients. Trust me, just warm them up a little and it will be so much easier.

These baked mashed potatoes are very adaptable to your family’s preferences and whatever ingredients you happen to have on hand.

Omit the bacon for a vegetarian dish. Use chives instead of parsley. You can even use Parmesan cheese instead of cheddar! Really, ANY type of cheese will be perfect here. Drizzle them with leftover gravy from scratch if you want!

I love a scoop of this alongside a helping of leftover Thanksgiving salad or Christmas salad.

Leftover mashed potato recipe casserole with overlay: Loaded Mashed Potato Bake

What can you put in a leftover mashed potato recipe for flavor?

My favorite flavorings are the ones I’ve added to this leftover mashed potato recipe:

  • sour cream
  • garlic powder
  • sharp cheddar cheese
  • bacon
  • green onion
  • red onion
  • parsley
  • crushed cheese crackers on top!

Can I freeze this leftover mashed potato recipe?

If you make this recipe using leftover mashed potatoes, I do NOT advise freezing it and reheating it again.

As a general rule of thumb for food safety, you only want to reheat leftovers once. Anything left over after that, you should discard.

However, if you make this recipe using “fresh” mashed potatoes (mashed potatoes you made immediately before making this casserole), you can freeze it.

Bake the frozen casserole straight from the freezer at 350 degrees F until the internal temperature of the casserole reaches at least 165 degrees F.

Psst – if you love the flavors in this recipe, you will also like my Baked Potato Pizza!

More tasty mashed potato recipes:

Mashed potatoes are my very favorite comfort food, and I never get tired of trying new and interesting flavor combinations!

Closeup of loaded mashed potato bake casserole with wooden spoon in it.

Loaded Mashed Potato Bake (Leftover Mashed Potato Recipe)

Yield: 4 servings
Prep Time: 20 minutes
Cook Time: 25 minutes
Total Time: 45 minutes

Looking for a leftover mashed potato recipe? This Loaded Mashed Potato Bake casserole is the most delicious way to use up leftovers. It's loaded with bacon, cheese and sour cream!


  • Nonstick cooking spray
  • 1/4 cup coarsely crushed cheese crackers
  • 1 tablespoon unsalted butter, softened
  • 2 cups mashed potatoes
  • 1/3 cup sour cream
  • 1/4 teaspoon garlic powder
  • 1/4 teaspoon ground black pepper
  • 4 ounces shredded sharp cheddar cheese
  • 4 slices oven baked bacon, crumbled
  • 1/4 cup finely chopped red onion
  • 2 tablespoons thinly sliced green onion or chives
  • 1 tablespoon chopped fresh parsley


  1. Preheat oven to 350 degrees F. Spray medium casserole dish with nonstick spray. In small bowl, stir crackers and butter until well combined.
  2. If leftover potatoes are cold, place in a medium microwave-safe bowl and microwave 1 minute to soften. Add sour cream, garlic powder and pepper to potatoes; stir until well combined.
  3. Reserve 2 tablespoons each cheese and bacon. Add red onion, green onion, parsley and remaining cheese and bacon to potatoes; stir until well combined.
  4. Transfer mixture to prepared casserole dish and sprinkle with cracker mixture and reserved bacon and cheese. Bake 25 minutes or until heated through.

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Nutrition Information:
Yield: 4 Serving Size: 1
Amount Per Serving: Calories: 382Total Fat: 26gSaturated Fat: 12gTrans Fat: 1gUnsaturated Fat: 10gCholesterol: 59mgSodium: 775mgCarbohydrates: 24gFiber: 2gSugar: 3gProtein: 14g

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Collage of images of potato, cheese and bacon casserole in white dish with overlay: LOADED MASHED POTATO BAKE make with leftover mashed potatoes!