Leftover Mashed Potato Pie with Cheese and Onion




This leftover mashed potato pie is something my mum used to make regularly for me. No idea why it’s called pie. There’s not one touch of pastry involved. In all honesty, this dish is just fluffy leftover mashed potato mixed with loads of cheese. A few onions are thrown in for good measure.


This leftover mashed potato pie is really filling. As a kid, I would eat it as my dinner, with white sliced bread. Carb overload, or what? But that’s how we rolled in the early 80s. I would have a side of pickled beetroot and a healthy dollop HP sauce all over it. Sounds so odd when I write it, but it really is my ultimate comfort food.


I no longer eat store bought white sliced bread, but I think my super soft bread rolls would be the perfect replacement. Although it’s most definitely a meal in itself, my leftover mashed potatoe pie also makes an awesome side, served up with meat (or even a roast dinner).



I only make it when I have made mash though (hate peeling potatoes), and it is a great way of using up any leftovers. Because this is a leftover dish, there are no strict measurements; just use as little or as much as you have. For the amount of cheese, again, that’s personal preference (the stronger, the better though). This time I used chilli cheese, which was awesome. 

If you like this leftover mashed potato pie, check out my other savoury recipes.


Leftover Mashed Potato Cheese and Onion Pie

Course Side Dish
Cuisine British
Prep Time 5 minutes
Cook Time 30 minutes


Leftover Potato Pie (see notes)

  • Leftover mash potato (cold)
  • 1 red onion (finely chopped)
  • cheese (any)
  • salt & pepper (to taste)


  • Pre-heat the oven to 200°C. Grease an oven dish.
  • Chop the onion.
  • Grate as much cheese as you like.
  • Place the mashed potato in a large bowl, add in the onion and cheese (leave some cheese to sprinkle over the top).
  • Sprinkle remaining cheese and bake in the oven for around 30, just until the top is golden and the cheese has melted. Serve immediately with some nice meat or eat with soft bread. Enjoy!


As this is a dish created out of leftover mashed potato, I haven't included any specific measurements. Just adjust the other ingredients to personal preference, and match how much mashed potatoes you have.
This dish can be made with leftover mash, or you can make your own from scratch. 

Leftover Mashed Potato Pie with Cheese and OnionLeftover Mashed Potato Pie with Cheese and OnionLeftover Mashed Potato Pie with Cheese and Onion

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