Cheesy mashed potatoes are the ultimate in comfort food and side dish that can easily be prepared in advance. Gruyere gives this mashed potato bake a cheesy flavour while still heroing those creamy potatoes.

  • Simple to make.
  • Creamy and cheesy but not overpowering.
  • Can be made ahead.
  • Baking gives them a gorgeous fluffy texture.
  • Loaded with chives.

I wanted cheesy potatoes where the cheese taste didn’t overpower the potato itself (as can often happen in cheesy mash recipes). To do this, you just need one type of cheese – I use gruyere but a good cheddar works too.

The result is this perfectly cheesy and super creamy mashed potato casserole. While you can eat the mash without baking it, and it is really lovely, baking actually gives an even fluffier texture to the potatoes and it also happens to make them so easy to make ahead of time.

This recipe was adapted from my fluffy mashed potato recipe.

Top down view of cheesy mashed potatoes in a baking dish.

Ingredients you’ll need

Ingredients for cheesy mashed potatoes.

Detailed quantities and instructions in the recipe card below.

The best potatoes for mashed potatoes

It seems smart to start with the best potatoes for mashed potatoes and it’s different depending on where you are. In the US, Yukon Gold potatoes or Russet potatoes work great. Here in Australia, Nadine or Royal Blue potatoes (my fave) work best. In the UK, look out for Maris Piper and King Edwards for best results.

The rest of the ingredients

  • Cheese: Many cheesy potato recipes use a number of cheeses to give an intense cheesy flavour. To keep things simple, my recipe calls for just one – Gruyere cheese – and just enough to be complimentary and not overpowering. You can add more if you like and you can also swap it for a good quality cheddar.
  • Milk: Use whole milk for this recipe for the best creaminess.
  • Crème fraiche: Crème fraiche (pronounced krem fresh) is a thick, tangy cream, very similar to sour cream. It has a higher fat content than sour cream giving these cheesy mashed potatoes a rich flavour but you can swap it for sour cream if you prefer.
  • Butter: Use unsalted butter so you can control the salt content to your liking.
  • Onion powder: One flavour that compliments both cheese and potatoes well is onion so a little added onion powder in this is amazing.
  • Chives: Adding to that oniony theme, loads of chives add more wonderful onion flavour.
  • Salt and pepper: A little salt and pepper for seasoning and that’s it.

How to make it (step-by-step)

A collage showing how to make mashed potato bake.

Detailed quantities and instructions in the recipe card below.

  1. Prepare the potatoes: First, you want to peel and cut the potatoes then give them a good rinse to remove excess starch.
  2. Cook the potatoes: Now boil the potatoes for 10-12 minutes until they easily break apart with a fork – we’re going a little past fork tender to crushable here.
  3. Drain and steam the potatoes: Drain the cooked potatoes then return to the pan, over heat, giving them a shake every so often for a minute or so. This steams away any excess water that we don’t want in our mash.
  4. Mash the potatoes: Give the potatoes a rough mash. Add the butter, milk, crème fraiche and seasonings and mash until as smooth as you like. You can keep mashing until perfectly smooth or leave them a little lumpy, it’s all good.
  5. Add the cheese and chives: Now we add the cheese and chives and mix them through until the cheese is melted. You can return it to low heat if you need, at this point, to get that cheese melted.
  6. Bake: Whilst you could eat the cheesy mash as it is, I like to take it one step further by baking for around 30 minutes. It adds a lovely golden top and actually makes the texture even fluffier.

Tips and tricks

  • Cut the potatoes the same size: Cutting the potatoes the same size will allow them all to cook evenly.
  • Rinse: Rinse the cut potatoes before cooking to remove excess starch.
  • Start with cold water: Put the potatoes into cold water then bring to a boil. This helps with even cooking.
  • Dry the potatoes: Heat the drained potatoes, shaking the pan often, for about a minute or so. This steams away excess moisture so your mash doesn’t turn out runny.
  • Warm the milk: Keeping the mash warm helps you mix it together more easily and allows it to remain hot enough to melt the cheese.
  • Let it come to room temperature: If making this ahead of time, let the mash in it’s casserole dish sit at room temperature for 45 – 60 minutes. If you add it straight to a hot oven, the dish may crack. You can also just make the mash, then add it to your casserole dish right before baking.

You can also use baked potatoes to make your mashed potatoes and this removes the chance of excess water getting into the mash and making it runny.

Team it up with these tender roasted shallots too.

A mashed potato bake with a scoop taken out.

Yield and storage

This cheesy mashed potatoes recipe is enough to serve 8-10 people. This recipe can very easily be scaled to suit a smaller serving.

Making it ahead

You can make this baked mashed potato ahead of time too. Once it’s in the casserole dish, let it cool to room temperature, cover with plastic wrap, then refrigerate 2-3 days before baking (it can also be frozen for up to 3 months – thaw before baking). Be sure to take it out of the fridge 1 hour before baking so the dish is not too cold as cold glass or ceramic could crack going straight into a hot oven. You can also just prepare the mash, then only put it into the baking dish right before you bake it.

Storing leftovers

Leftover cheesy mash can be stored, covered, in the fridge for 2-3 days (depending on how far in advance you made it – don’t go beyond 4 days storage). The mash also freezes well for up to 3 months but thaw it before baking. Thawing can take up to 24 hours in the fridge.

A dollop of mashed potatoes on a small plate.

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Mashed potato in a casserole dish with a scoop taken out.

Cheesy Mashed Potatoes

5 from 1 rating
These cheesy mashed potatoes are creamy, fluffy and absolutely crave-worthy. Easy to prepare, this baked mashed potato casserole can be made ahead of time.

Ingredients

  • 1.8 kg potatoes (like Royal Blue, Nadine, Russet, Maris Piper) (4lb)
  • ½ cup whole milk, warmed (125ml)
  • 115 g unsalted butter, room temperature (½ cup / 1 stick)
  • ¾ cup creme fraiche (or sour cream), room temperature
  • 1 teaspoon onion powder
  • 2 teaspoons finely ground sea salt
  • ½ teaspoon cracked black pepper
  • ½ cup finely chopped fresh chives (25-30g / 1oz)
  • 2 ½ cups firmly packed shredded gruyere (or cheddar cheese) (280g / 10oz) (notes)

Equipment

Instructions
 

  • Peel the potatoes and cut into roughly 1 ½ inch pieces.
  • Rinse them through a colander to remove excess starch.
  • Place potatoes in a large pot or dutch oven and cover with water.
  • Bring to a boil over high heat and boil for around 15 minutes until they break apart easily when you push a fork through. Cooking time will depend on the size you’ve cut them and the type of potatoes you use.
  • Drain the potatoes and return to the pot over medium heat for around 30-60 seconds. Let them steam, shaking the pan quite regularly to dry them out. Remove from heat.
  • Preheat the oven to 180C (160C fan) / 350F.
  • Mash the potatoes roughly (or push them through a potato ricer) then add the butter, milk, creme fraiche, onion powder, salt and pepper. Mash until combined and desired consistency (smooth or just a little lumpy is up to you).
  • With a wooden spoon, stir in ⅓ cup of chives and all the gruyere until melted then transfer to a 9×13 inch / 23×33 cm casserole dish.
  • Bake for 30-35 minutes until starting to turn golden on top.
  • Top with a little melted butter, if desired, then sprinkle over some cracked pepper and remaining chopped chives.
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Notes

Flavours

  1. These mashed potatoes have a subtle cheesy flavour. To make it even cheesier in flavour, you can mash in 1/2 cup of parmesan cheese. You can also add up to 120g / 4oz of cream cheese.
  2. You can use other fresh herbs too. Thyme leaves are lovely. Finely chopped rosemary or sage is good too.
  3. If you want cheesy garlic mashed potatoes add a clove or two of minced garlic while mashing.
  4. You can also use finely chopped spring onions (scallions or green onions) in the bake in place of the chives. They have a stronger flavour than chives, so I would skip adding them raw on top.

Making ahead

  1. Can be made ahead 2-3 days before baking.
  2. If making this ahead of time, let the mash in it’s casserole dish sit at room temperature for 45 – 60 minutes. If you add it straight to a hot oven, the dish may crack. You can also just make the mash, then add it to your casserole dish right before baking.

Other tips

  1. You can use a hand mixer or stand mixer on low to mash and combine everything too.
  2. Make sure ingredients are at least at room temperature and the milk warmed so the mash stays hot enough to melt the cheese.
  3. Don’t skip steaming the potatoes to dry them out.
MORE WONDERFUL SIDE DISHES!
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