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Truffle Potato Gratin with Gruyere & Smoked Cheddar

Serves 8| Ready in 40 mins
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This truffle potato gratin is a twist on the classic potatoes au gratin and is layered with complex flavours, from the savoury umami-ness of truffle oil to the deep smoky-cheesy vibe of the smoked cheddar, nutmeg, garlic, sage, and thyme, all surrounded by a rich creamy sauce and, of course, golden-brown cheese for days.

Truffle Potato Gratin with Gruyere & Smoked Cheddar

Say hello to the ultimate holiday side dish. It’s so easy to make – and no peeling potatoes! A quick parboil in the creamy mixture, layering with cheese into your dish, and then the oven does the rest!

If you’ve never made a potato gratin before, read on to find each step clearly explained along with pro tips and some fun variations to try. I’m all about easy recipes that taste delicious, and I love showing ways to build flavour that doesn’t require a million steps and hours in the kitchen.

What is a potato gratin?

Simply put, it’s sliced potatoes cooked in cream, with added flavours, then baked in the oven with cheese until melted and golden brown, and the taters are tender and cooked through. There are similar dishes out there, like dauphinoise potatoes or scalloped potatoes, that use raw potatoes and no cheese. Tasty, yep, but if you’re a cheese lover, a gratin is the way to go. It’s a crowd-pleasing, low-effort dish perfect for special occasions like Thanksgiving or Christmas, or with a simple Sunday roast.

Flavouring the potato gratin

I like to think of a traditional gratin as a blank canvas… made of potato. Potato gratin with gruyere is almost a no-brainer – it’s the ultimate melting cheese, with a subtle, distinct flavour that complements a spud so well. Adding smoked cheddar to the mix is a revelation – I’ll never make potato gratin without it! The flavours are so rich and just yummy. But this dish really comes to life with the truffle oil. You get this mature, complex flavour that works with the smokiness and creaminess that you just can’t get enough of. I’m trying to think of more dishes that I can add this flavour combo to.

Other variations to try:

  • Add in some crispy pancetta for a meatier vibe – super yummy.
  • Caramelised onions or leek are also a delicious addition.
  • Substitute the top layer of cheese with some sourdough garlic breadcrumbs.
  • Change up the potato and try sweet potato instead!

A note about truffle oil

In order to make this dish as accessible as possible, this recipe is made with truffle oil, not whole truffles. But not all truffle oil is created equal! Make sure you buy the real stuff, not the synthetic kind that is made from chemicals. Real truffle oil is made with real truffles, infused with good quality olive oil. Synthetic truffle oil uses a chemical compound called 2,4-dithiapentane that is heat-treated to have a ‘truffle-like’ flavour. Not only is it unnatural, but the flavour is also completely subpar. Side-step that one. Check the back of the label if you’re not sure, or a quick Google will help you find a good truffle oil brand in your area.

Cooking tip and tools:

  • My pro tip is to parboil the potatoes. Some gratin recipes skip this step, but it helps to ensure the potatoes will be perfectly cooked by the time the cheese is golden brown, plus the flavours have longer to infuse together and into the potatoes.
  • Check the potatoes after 20 minutes: Because everyone’s oven is different, naturally cooking time can vary, so checking to see the ‘done-ness’ of the potatoes and if the cheese has any colour will be a good indication of how long to leave it in. I like to check every 5 minutes after just to get that perfect golden-brown colour.
  • Add the truffle oil at the end: Truffle oil is a finishing oil, only used at the end. If you were to add it in before baking, the flavour disappears, and it’s just a waste.
  • If preparing to go with a roast meat: This dish only takes about 30 minutes in the oven, so if you’re preparing this to go with a slow roast cooked at a lower temperature than 200 °C / 392 °F, it’s best to let the roast finish cooking, cover it to keep warm and rest, then turn up the heat to cook the gratin.
  • Tools and equipment: A mandolin is helpful, but totally not necessary. Just try to cut your potatoes at a similar thickness. All you need is a pot big enough for boiling 1 kg of potatoes and a baking dish about 30 cm / 11” in diameter if you choose a circular one.

What to serve with Truffle Potato Gratin

I’m glad you asked. Truffle is a distinct flavour that compliments so many meat dishes. My roast chicken with flavour bomb gravy is a fantastic pairing. If you’re serving a larger crowd, my roast lamb is also an absolute favourite. To make a complete menu for entertaining, a salad on the side is kind of a must, and this pear and prosciutto salad is an absolute must! It has complimentary flavours and is easy to prepare in advance.

Got a potato craving?

Here’s some more potato recipes that you'll love. Brown Butter Mashed Potatoes, Garlic Roast Potatoes, Roast potato salad, Roasted sweet potato salad, Seared salmon and roast potatoes.

Frequently asked questions
What potatoes are best for potato gratin?

I mentioned at the beginning this recipe has no peeling potatoes (woohoo!) and I meant it. So choose a simple white washed potato, the skin is thinner so won't notice it in the cooking.

Ingredients and substitutions

Ingredients to make A dish of Truffle Potato Grain with Gruyere and Smoked Cheddar
White-washed potatoes
Perfect for not having to peel! To substitute, a russet or sebago is good; it will just need to be washed and peeled.
Milk & thickened/heavy cream
I quite like the combination of both milk and cream cooked together for this dish.
Nutmeg
Adds a delicious autumnal flavour. I like to use whole nutmeg and grate it on a microplane; it’s so fresh and, dare I say, has an enchanting scent.
Fresh herbs
Thyme sprigs and sage leaves
Garlic cloves
To deepen the flavour of the sauce
Gruyere cheese & smoked cheddar
A delicious flavour combination. If you can’t find smoked cheddar, substitute with regular cheddar or parmesan cheese.
White truffle oil
Real truffle oil, not the fake synthetic kind. Substitute with black truffle oil if you can’t get access to white truffle oil.
Salt & pepper
For seasoning.

How to make it - step by step!

Slicing potato on a mandolin
1. Preheat oven & slice potatoes

Preheat the oven to 200 C / 392 F. Slice potatoes 3 mm / 1/8" thick.

Adding herbs to cream
2. Make the creamy sauce

Add the cream, milk, garlic cloves, grated nutmeg, sage and thyme leaves, salt and pepper to a saucepan. Gently bring to a boil, you don’t want a hectic rapid boil.

Simmering a pot of potatoes
3. Parboil potatoes

Add the potatoes to the milk mixture to parboil. Simmer for 6-7 mins, stirring occasionally.

Potato slices and grated cheese in a baking dish
4. Layer potato and cheese

Grease the baking dish with butter. Arrange ⅓ of the potatoes in the baking dish, sprinkle over ⅓ of the grated gruyere and cheddar cheese. Repeat with the rest of the potatoes and cheese, pour over the milk mixture and finish with a layer of cheese.

Baked potato gratin
5. Bake

Bake in the oven for 25-30 minutes, until the cheese is golden and the potatoes are cooked through.

Adding truffle oil to potato gratin
6. Finish with truffle oil

Remove from the oven, scatter with fresh thyme and finish with a drizzle of truffle oil over the top. Add an extra little pinch of salt and pepper.

Watch the how to video

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Truffle Potato Gratin with Gruyere & Smoked Cheddar

Cook Time
30 mins
Prep Time
10 mins
Serves
8
This truffle potato gratin is a twist on the classic potatoes au gratin and is layered with complex flavours, from the savoury umami-ness of truffle oil to the deep smoky-cheesy vibe of the smoked cheddar, nutmeg, garlic, sage, and thyme, all surrounded by a rich creamy sauce and, of course, golden-brown cheese for days.
  • 1 kg white washed potatoes
  • 350ml milk
  • 150ml thickened / heavy cream
  • 1/4 tsp nutmeg
  • 3/4 tsp salt
  • 1/2 tsp pepper
  • 4 thyme sprigs
  • 4 sage leaves
  • 3 cloves of garlic, finely diced
  • 100g gruyere cheese, grated
  • 150g smoked cheddar, grated
  • 1/2 tbsp (a drizzle) of white truffle oil
Category - Sides
Cuisine - French inspiredfr
Skill Level - Super easy
Other categories -
Sides, Christmas, Entertaining, Winter, Autumn, Vegetarian
Nutritional information
Calories 326.2 kcal16%
Carbohydrates 25.6 g9%
Sodium 459.9 mg20%
Magnesium 46.5 mg12%
Protein 12.8 g26%
Sugar 3.8 g4%
Calcium 346.8 mg35%
Vitamin A 14%
Fat 19.7 g30%
Fiber 2.9 g12%
Iron 1.2 mg7%
Vitamin C 31%

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