I spotted the ever-so-iconic Chef John post these and I’ve never seen anything more beautiful in my whole life. Grab your eating pants and follow me, because things about to get real delicious real quick.
Cheesy Mashed Potatoes
The first layer of this beautiful creation is mashed potato. I know everyone may already have their own ‘go-to’ mash recipe, which you’re welcome to use, but here are the usual suspects in mine:
Butter – and lots of it! Cream – or you could use whole milk. Cheese – I use cheddar, but you could use comte or gruyere. Seasoning – potatoes LOVE salt so don’t hold back!
You’ll want to start off with cold water and bring to a boil, as this will help the potatoes cook through evenly. From there, drain them and let them sit for 1 minute. This will help some of the moisture escape and prevent the mash from being watery. During this time I recommend melting the butter and warming the cream using the residual heat in the pot. Doing this will help the potatoes absorb both of them without turning the mash clumpy. Process shots: boil potatoes (photo 1), drain (photo 2), warm butter and cream (photo 3), add potatoes (photo 4), mash (photo 5), mash in cheese and seasoning (photo 6).
Potato Gratin
On top of the mash goes a potato gratin i.e. thinly sliced and stacked potatoes. To ramp up the flavour I love adding in some garlic and parmesan, just to make the topping extra special.
Do I have to pre-cook the potatoes on top?
Nope! They cook through in the oven and crisp up beautifully. If you slice them thinly they’ll be perfectly tender by the time the whole thing is done. Process shots: peel potato (photo 1), halve (photo 2), thinly slice (photo 3), melt butter then add garlic and seasoning (photo 4), toss in potatoes (photo 5), toss in parmesan (photo 6).
Mashed Potato Gratin
To combine everything, just plonk the mash in a baking dish and level off with a spoon or spatula. From there, you can top with the garlic parmesan potatoes. You’ll want to stack them fairly tightly and at a slight angle. To bake the whole thing, I find the best method is to do a portion of the cooking with foil on, then remove it for the bulk of the time. The foil will trap the steam and help the potatoes cook through without them browning too quickly. Process shots: add mash to baking dish (photo 1), stack potatoes (photo 2), bake with foil (photo 3), remove, top with parmesan and bake again (photo 4).
What kind of potatoes should I use?
Use a floury/baking potato such as a Maris Piper (UK) or Russet (US). Or simply ones in the store that say ‘Baking Potatoes’. These will give the best texture for both the mash and gratin.
Do I have to add the garlic?
Nope! You can leave this out if you’d prefer.
How do I make sure the potatoes are cooked through?
If they’re sliced thinly and you bake for the full hour, they will be fork tender. If they’re not, just add the foil back on and continue baking.
Serving Mashed Potato Gratin
Once out of the oven it’s essential that you let it rest. This will not only allow the mash to retain its shape, but it’ll also give time for the gratin to finish cooking through. I love to finish with some fresh chives, but they’re optional. This is the perfect Side for just about everything and works perfect as part of a Roast Dinner! Alrighty, let’s tuck into the full recipe for this mashed potato gratin shall we?!
How to make Mashed Potato Gratin (Full Recipe & Video)
