Recipe: Truffled Mashed Potatoes with Wild Mushrooms, Garlic & Gruyere Cheese

Adapted from a Nigel Slater recipe, this is a luxurious, comforting dish that stands alone as a vegetarian main course.

It’s delicious as an accompaniment to roast ham, meats or poultry. Potato lovers will love the combination of truffle, mushrooms sautéed in garlic and melted cheese. Truffles have a wonderful affinity for potatoes – maybe because they both live underground.

If you were lucky enough to find wild porcini mushrooms last year (see my blog; ‘It’s Hunting Season’ posted last August), hopefully you sliced and sautéed the smaller perfect specimens in butter and a little olive oil then froze them for a dish such as this. Likewise chanterelles but these can be purchased in season if you can’t find them yourself.

BTW, don’t worry if you’re nervous about picking wild ‘shrooms (I studied mycology before venturing into the woods with a basket, knife and insect repellant so I know what I’m doing) – this is spectacular when made with just *portabellas so there’s no risk of wildly tripping-out or perhaps worse, poisoning your dinner guests.

I don’t use shitake for this recipe. They’re great in other things but their musty-old-book taste doesn’t work here.

You can buy dried porcini in good supermarkets; they’re a bit expensive so obviously finding and drying your own is preferable and last season yielded enough for a whole year of mushroom-gluttony.

Reconstituted dried porcini have a wonderfully intense, almost meaty flavor and their soaking liquid should always be used somehow; even if to enrich some soup or sauce.

I’m suggesting alternative ingredients below and the end result is still delicious. Invest in some black or white truffle oil because you don’t need much to perfume any dish; keep it in the fridge to prevent it turning rancid.

You can assemble this 2- 3 days ahead of time and keep it covered in the fridge or freeze it. If freezing, wait until it’s fully defrosted before you scatter the grated cheese and truffle oil on top, prior to baking.

Notes at the end with fungi translations:

Mashed Potatoes with Porcini & Gruyere


(Serves 4 as a main dish, 6-8 as a side dish – adapted from a Nigel Slater recipe)


3 ½ lbs/1.5 kg of smallish red skinned potatoes

2 oz/50g of butter

¼ pt/100ml of hot milk

2 eggs, beaten

4 oz/100g of ‘Cacio di Bosco’ (a Tuscan Pecorino cheese laced with bits of black truffle) OR – the very best quality Parmesan, finely grated

Truffle oil

For the mushroom layer:

12 oz/350g of mixed fresh porcini, chanterelles and portabella/large-capped field mushrooms (use just portabella if you can’t find the other varieties)

Half a cup of dried porcini mushrooms; soaked in hot water for 20 mins

2 fat cloves of garlic, chopped

2 heaped tablespoons of Italian flat leaf parsley

Sea salt, freshly ground black pepper

8 oz/200g of best quality Gruyere cheese; cut into half-inch cubes


Butter an 8-9 inch wide, fairly deep baking dish

Cook the whole potatoes in boiling salted water until tender; drain, cool a bit and slip the skins off. Mash with the 2 oz butter and hot milk then stir in the beaten eggs and 2/3rds of the grated Parmesan or Pecorino with truffles. (If using Parmesan add ½ a teaspoon of truffle oil and mix well. You’ll know if you need more so keep adding a very little at a time until it’s gently fragrant with truffle)

While the potatoes are cooking, slice the mushrooms and sauté in the butter with garlic until the mushrooms are soft and the garlic golden. If like me you’re using previously frozen wild ‘shrooms cooked in butter, just cut back on the butter, heat them through then add the portabellas and garlic and cook together. Its hard to overcook a mushroom when there’s butter involved.

Chop the soaked porcini mushrooms and add with their soaking juice to the mushroom garlic mixture. Turn up the heat and reduce the soaking liquid, stirring until there’s not much left. Mix in the chopped parsley and season with sea salt and freshly ground black pepper. Set aside.

Spread half of the potato mixture on the bottom of the dish then scatter the cubed Gruyere cheese over.

Cover this layer with all of the mushroom mixture then spread the rest of the potato mixture on top. If you’re going to cook this immediately or in the next couple of days, scatter the remaining 1/3 grated Parmesan/Pecorino on the top and drizzle a little truffle oil over.

To bake; preheat the oven to 375F/190C and cook 30-45 minutes or until golden on top and your kitchen smells wonderful.

Reheat any leftovers in a warm oven.

Buon appetito!


truffled-wild-mushroom-mash-with-gruyereEveryone in the US knows what a Portabella mushroom is. The equivalent in the UK would be those large, flat, open field mushrooms with dark pink to black gills. Or use the smaller brown chestnut mushrooms which are more interesting than the ubiquitous white ‘champignon’ variety.

Eggs have an equal affinity for truffle so whether they’re baked, omelet-ed or scrambled, the addition of truffle oil, truffle salt, or if you’re really lucky and can afford the real thing, a few shavings of fresh truffle will take eggs to another level.

Likewise, truffles love a baked potato. And pasta with a simple Alfredo type of sauce. Truffle-scented plain mashed potato is great with steak, roast game, broiled lobster – or eat it on its own, mashed with lots of butter and a grating of your favorite cheese.

About edibletcetera

I'm passionate about food; I cook, photograph, eat...then writes about it in that order. I'm also an occasional restaurant critic and caterer; a former newspaper columnist; author; social media/marketing communications; world traveler; dog lover; skier...and wit, (according to those who know me).
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1 Response to Recipe: Truffled Mashed Potatoes with Wild Mushrooms, Garlic & Gruyere Cheese

  1. Sue Ellen says:

    Sounds yummy.

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