As we are still in the middle of comfort food season, I decided to make a deliciously comforting mushroom pie with potato rosti recipe. For me it was love at first sight as I love mushrooms and potatoes in equal measure. This dish is reminiscent of my interpretation of Lancashire hotpot that so many of you love, but it’s a little different.
I wanted the filling of this simple mushroom pie be both mushroomy and garlicky as these two flavours just belong together. Pan-fried mushrooms with garlic butter used to be one of my favourite childhood dishes my mum used to whip up when she was in a pinch.
I used three different types of mushrooms – shiitake, oyster and chestnut – which I pan-fried in two batches to get their beautiful texture to shine. No mushroom sliminess here, they are juicy yet lightly charred in a hot skillet. I amplified the mushrooms with some lentils to make the dish more substantial and topped the filling with a tangle of shredded potatoes, which gets delightful soft and crispy in a hot oven. This mushroom pie skillet is an absolute cold weather dream. We loved this effortlessly vegan and gluten-free dish and I hope you’ll too.
MORE ABOUT THE INGREDIENTS
MUSHROOMS: Mushrooms are the star of this mushroom pie so get the best you can find. I recommend getting a few different varieties so that the resulting pie has a lot of texture but if that’s not available using one type (like standard white mushrooms) is absolutely fine too. I used a combination of brown chestnut (known as cremini in the UK), oyster and shiitake mushrooms.
LENTILS: Lentils are a reliable backing singers in this dish, they are super convenient (I used a can of lentils, but they also come in pouches or TetraPaks these days) and pack a lot of nutrition into this dish. I recommend using a firm variety like Puy or green lentils rather than red lentils.
POTATOES: For the best crispy topping, pick a variety of potatoes that contains a lot of starch. These types of potatoes are best for baking and roasting. Their name varies from country to country so unless you happen to live in the UK, find a variety that fits this description where you live. In the UK, Maris Piper or King Edward (that’s what I used in this dish) varieties are best. In the US, russet potato is a common starchy variety.
MISO: Miso is a fantastic savoury flavour carrier and happens to go so well with mushrooms. I used dark miso paste*” rel=”noopener” target=”_blank”>dark miso (also known as red although it’s brown) as it has a deeper flavour but white miso (which is confusingly yellow in colour) will work too. If neither are available, that’s okay. Simply use a bit more soy sauce and maybe a touch of yeast extract (like Marmite). If you are making this dish for someone who cannot have gluten be sure to find gluten-free variety of miso or skip it.
SOY SAUCE: Soy sauce is a beautiful flavour enhancer and it also seasons things so I used it here instead of salt. If making this dish for someone who is gluten-free, use tamari instead of soy sauce as it’s brewed without wheat.
THYME: Thyme is such a trusty mushroom companion that I don’t think it needs any explanation. I used fresh thyme leaves (picked from the stems) but you can use good quality dried too. They are more potent so only about a teaspoon should be equivalent to one tablespoon fresh leaves. Alternatively, use another hardy herb like rosemary or sage or a combination of the two.
GARLIC: So my plan is to make this dish really garlicky and mushrooms and garlic are heaven in my book! I sauteed two fat cloves in oil and grated another fat clove straight into the sauce just before baking for even more of a garlicky kick. If you are not a fan, skip this addition of course, but do so at your own peril…(vampires abound).
SHALLOTS: Shallots and mushrooms, do I need to say more? Thet belong together…and garlic too, of course. But on a serious note, it’s fine to just use a small-medium onion, white or red.
OLIVE OIL: I used some olive oil to sautee my aromatics and to char my mushrooms and a bit more to make the potato rosti beautifully crispy. I didn’t want to go overboard so used 4 tbsp in total, but you can also go crazy if you like.
CORNSTARCH: I used a small amount of cornstarch to thicken the sauce a little and I tossed some through my grated potato strands to give them more of a crunch once baked. No regrets!
OAT CREAM or MILK: I used oat cream single cream and a bit of water to make the filling, but you can also use a full fat oat milk instead of water and cream. Both are delightful.
HOW TO MAKE IT?
1) PAN-FRY AROMATICS AND MUSHROOMS
Grab a 26 cm / 10 inch oven proof skillet and pan-fry aromatics in a small amount of oil, then mushrooms in two batches – adding oil only after all the excess moisture that mushrooms release has cooked out.
Don’t hesitate to get these mushrooms charred in places – this maximises flavour! If you are dealing with mushrooms that are a bit floppy – like oyster mushrooms – weigh them down with a heavy pan for a bit – to flatten them and ensure a good char.
2) MAKE THE FILLING
Once the mushrooms are ready add the rest of the filling ingredients to the pan, including cornstarch slurry (it will thicken the filling a little). Taste and adjust the seasoning to your liking. Although both miso and soy sauce contribute salt, my guess is that you will want to season the mixer a touch more, but do taste before adding any extra salt.
3) GRATE POTATOES
Par boil your potatoes until partially cooked but tender enough to grate. I used very large (200 g / 7 oz each) potatoes and parboiled them for 10 minutes. Once parboiled, allow them to cool down and grate using a food processor or by hand. Toss grated potatoes with some oil, cornstarch and salt.
4) ASSEMBLE & BAKE
Finally assemble the pie but topping the filling you prepared with the rosti mixture. Make sure to leave a thin margin all around the pan. Bake until the filling is bubbling and the rosti is crispy – about 40 minutes.
ROSTI TOPPING
- 400 g / 14 oz (2 large) starchy potatoes*
- ½ tsp salt, more to taste
- 30 ml / 2 tbsp olive oil
- 1 tbsp cornstarch
MUSHROOM PIE
- 700 g / 24.5 oz mixed mushrooms*
- 30 ml / 2 tbsp olive oil
- 2 banana shallots or 1 medium onion, finely chopped
- 3 large garlic cloves, divided
- 1 tbsp red miso paste*, adjust to taste
- 1 tbsp soy sauce (or tamari if GF)
- black pepper
- 250 g / 9 oz (1¼ cups) cooked Puy OR green lentils (1 can)
- 240 ml / 1 cup oat cream OR 360 ml / 1½ cup oat milk
- 4 tsp wholegrain mustard, more to taste
- 1 tbsp fresh thyme leaves
- ½ tbsp cornstarch
- Parboil potatoes for 6-10 minutes, depending on size, so that they are partially cooked but still firm enough to grate. I used two large (200 g / 7 oz each) potatoes so I boiled mine for 10 minutes. You can peel them if you like, I didn’t bother. Rinse in cold water and set aside to cool.
- Prep your mushrooms, I sliced shiitake and chestnut mushrooms into thick slices and tore large oyster mushrooms into 2 pieces with my hands so that my filling has a variety textures.
- Preheat a 26 cm / 10 inch heavy oven proof skillet, add 15 ml / 1 tbsp of olive oil and chopped shallots. Sauté on low heat until almost transparent, the add 2 sliced garlic cloves and fresh thyme. Carry on sautéeing until cooked, then remove from the pan.
- Increase the heat and add about half of the mushrooms to the skillet with a pinch of salt. Allow the water to cook out and for the mushrooms to turn brown. Remove from the pan and add the rest of the mushrooms. When the second batch is done, return the first portion of mushrooms to the pan and stir in 15 ml / 1 tbsp of olive oil. Allow mushrooms to char in places then remove from the pan.
- Return shallot mixture to the pan, add lentils, 240 ml / 1 cup of oat cream and 120 ml / ½ cup of water (or 1½ cups of oat milk instead). Dilute cornstarch in a bit of liquid first, then stir in miso, wholegrain mustard and freshly grated clove of garlic – add all of this to the dish. Season with black pepper and soy sauce. And you may want to add a touch more salt but do taste first.
- Preheat the oven to 200° C / 390° F (or 180° C / 350° F with a fan on).
- Grate parboiled potatoes coarsely – I used a food processor but you can also do that by hand. Place grated potatoes in a mixing bowl. Using your hands, toss them in 2 tbsp of olive oil, 1 tbsp of cornstarch and ½ tsp of salt.
- Spread potato mixture on top of the pie leaving a thin margin all around. Bake until the filling is bubbling hot and the rosti is crispy and golden – about 40 minutes. Consume immediately.
*MUSHROOMS: I used a mixture of oyster, shiitake and chestnut (cremini) mushrooms. You can use only plain white mushrooms but I find that this pie is a lot better with different mushrooms as each time contributes different texture making the dish more satisfying.
*MISO: If making this dish for someone who cannot have gluten, find gluten-free miso or skip and add more tamari (GF soy sauce).