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Leftover Mashed Potato Casserole

A simple casserole that can be thrown together easily. Perfect when you're craving some perogies, can't find any, and don't want to try to make your own.

Course Lunch, Main Course
Cuisine American
Keyword Oven
Prep Time 20 minutes
Cook Time 1 hour
Total Time 1 hour 20 minutes
Servings 4 people


  • Mashed Potatoes Leftovers originally made with milk
  • Eggs
  • Bacon Diced and cooked
  • Cheddar Cheese Grated


  • Milk
  • Garlic Powder
  • Onion Powder
  • Crushed Red Pepper Flakes
  • Red Peppers Diced and softened

Toppings (Optional)

  • Greek Yogurt
  • Sour Cream
  • Chives


  1. The base of this recipe is mashed potatoes so you'll either need enough leftover mashed potatoes from another meal or make some specifically for this recipe. To make mashed potatoes peel potatoes (I normally use russet) and cut them smaller if you want it to cook faster. Add water, bring to boil, and simmer until they're tender enough to pierce with a fork. Drain the water off and return the potatoes to the pot. Add milk and mash until smooth. Optionally, you could season it with butter, pepper, salt, garlic powder, or onion powder.

  2. Diced cooked bacon is another ingredient needed. One way to make it is to lay it out on lined cookie sheets and bake it in a hot oven before cutting it into small pieces. Another way is cut it smaller, while raw, and then use your frying pan to cook it. Either way you'll want small cooked bacon pieces. If you want to add onions, diced peppers, or anything else that needs precooking you can add it to the bacon while it's cooking to save a step.

  3. Grab a large bowl and add together the leftover mashed potatoes, diced bacon, eggs, grated cheddar cheese, milk if it's too thick, and any seasonings you need like garlic powder, onion powder, or crushed red pepper flakes. If you want to top the casserole with anything (additional cheese or bacon for instance) you'll need to keep some back. Once everything, except the toppings, are added you can mix it together and either go onto the next step or seal it in the fridge to cook later that day if you're prepping earlier.

  4. Once you're ready to bake the casserole preheat your oven and dump your casserole contents into a casserole dish. After you flatten the casserole it's either ready or you can add any additional toppings like more bacon or cheese. A cooler oven means you'll have to cook it longer and a hotter one you'll want to keep more of an eye on it. If you don't want the top to cook quicker than the rest you can cover it in tinfoil and remove it for the last fifteen minutes. I normally bake mine at 375° Fahrenheit for about an hour. If it's ready and not browned enough you can always turn on the broiler, casserole uncovered, to finish it off.

  5. Once done dish and serve. I always top mine with Greek yogurt (tastes just like sour cream) though you can use anything you'd normally serve on your perogies.