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Fish Pie with Truffle Potato Mash

Updated: Dec 28, 2023

Prep: 30 min // Bake: 30 min


There’s nothing more comforting than a warming fresh fish pie during the cold months. Sweet, super healthy leeks thrive during winter (in season October to March) and combined with potato mash and cheesy textures make it a pure food for the soul. This dish is a typical English meal that Britain can be proud of giving to the world. We, Mediterraneans living in the UK, appreciate it and honour it much ;-) Moreover, I find this pie is one of the best ways to introduce fish and seafood to a baby toddler when weaning but also a family weekend superfood being rich in omega fats, and the goodness of leek (vitamins A, B, C, K, iron and manganese).


There are plenty of recipes out there which as you will notice reading through, are more or less similar with small variations in herbs, types of fish, and the addition of other seafood (e.g. prawns). My version is a bit pumped up with flavour by the introduction of tasty dijon mustard, parmesan and cheddar in the filling, and the fusion of the mash topping with Mediterranean truffle oil. It’s relatively easy to make, you just cook everything in a pot and lay it in an ovenproof dish to bake. How wrong can that go? Just make sure you buy some good quality ingredients (my recommendations at the end of this post).

Ingredients (6-8 servings)

For the filling:

  • 500g skinless-boneless haddock fillets

  • 250g skinless-boneless salmon fillets

  • 2 leeks

  • 100g plain flour

  • 80g unsalted butter

  • 100g Philadelphia light

  • 800ml low-fat milk

  • 1 handful of fresh dill, finely chopped

  • 50g grated parmesan

  • 50g grated cheddar

  • 2 tbsp Dijon mustard

  • ½ tsp nutmeg

  • 1 unwaxed lemon, juice and zest

  • 1 handful of capers (optionally)

  • Salt and pepper

For the truffle mash:

  • 1kgr floury potatoes (around 4 large ones)

  • 60ml low-fat milk

  • 50g unsalted butter

  • 1 tbsp truffle oil

  • Few gratings nutmeg

  • Salt and pepper


There’s plenty of room here for experimenting; first of all, haddock can be switched for any other firm white fish of the cod family; smoked versions also work smoothly adding extra flavour. Salmon is a basic ingredient that I’d recommend keeping in the recipe. In the cheese section, I’d also easily switch parmesan and cheddar with graviera and feta and would also add some capers to bring on a more Greek Mediterranean kick. Dijon mustard can be substituted with any variant, from sweet mild American to Dijon or even English. The spiciness of Dijon or English mustard is balanced by the milk in this recipe and the result is not spicy at all, perfectly suitable for kids.

Truffle oil in the mash is my latest addiction, a powerful taste idea I’ve borrowed from a lovely Mediterranean fusion restaurant we often visit in London, and also a great Meditteranean connoisseur’s ingredient which I lately started using in my cuisine. In absence of truffle oil, just completely omit it from the recipe, mash still tastes awesome without it. I have some recommended products down the end of the post as usual.


  • Take a moment to read through all the steps before starting, and make sure you’ve got all the ingredients ready.

  • Peel and cut the potatoes into 1 to 2-inch chunks (so they quickly boil) and add them into a pot (with a matching lid) of boiling water. Cover and boil for 15 min.

  • While the potatoes are boiling, prepare the rest: top and tail your leeks, remove the outer layers and finely slice them. Finely slice the dill and set aside. Remove skins and any remaining bones from the fish fillets and cut them into bite-size chunks. Measure 800ml milk and warm it up in the microwave.

  • In a large pan under medium heat melt 80g butter with some olive oil and start sweating your leeks in low heat. When softened, add the flour and whisk continuously until leeks are covered. Add the milk little by little, stirring continuously until you have a smooth thick sauce.

  • When the sauce starts bubbling add the Philadelphia, all the dill, the parmesan and cheddar, the 2 tbsp mustard, 1 lemon juice and zest, season with salt and pepper and stir until everything melts and blends.

  • Remove the pan from the heat, stir the fish chunks in and set aside to cool down until you prepare the mash.

  • Preheat your oven to 200c (180c fan).

  • Make the truffle mash: in the pot with the boiled and drained potatoes add the butter, milk, the truffle oil, nutmeg, season with salt and pepper and mash them with a potato masher until smooth.

  • Pour the fish mixture into a large ovenproof dish and spread the potato mash on top evenly. Run a fork over the surface to make patterns (I like sea waves) and bake for around 30-35 min until it’s golden and edges slightly charred on top.

Recommended Products

Below you will find my favourite authentic products (affiliate links) I used to cook and shoot this recipe. If you can't see the content, please deactivate your ad-blocker and refresh the page :-)

Shop the look:


Although appearing very discreetly in my images, I own quite a few bought from Amazon. They are so good value for money, you won't believe they are only a fraction of the price you'd pay at Zara or H&M. Not only we use them on our regular dinner nights with friends but also serve as textured backgrounds for my photos. I like linen and tassels, below are two of my favourites featuring in my photography.


I am addicted to mustards. And specifically, deli mustards mixed with herbs and other fancy ingredients.

If you ever visit France, look for 'Le Comptoir De Mathilde' deli shop chain and buy a pack of mustards to bring home (along with some exceptional praline spreads). Their mustard with Provence herbs is simply out of this world!

If you are not in France and not willing to pay the extra shipping costs from France, I'd recommend the very tasty Tracklements range, or go one step further for some French deli brands available in the UK (links below). A bit pricier, but as always in foods, you get what you pay for. And you can absolutely use it in other recipes, marinades, sauces or sandwiches.

Truffle Oil:

I have no big experience in truffle oils, but the couple of brands I'm listing below are the ones I've tested and proved their excellence. When it comes to Olive Oil, look no further than Mediterranean oils, and especially the Greek olive oil, one of the most premium around the world. Dirfis is one of the most renowned brands in Greece and exports a high-quality truffle extra virgin oil that we can luckily find at Amazon. Alternatively, Belazu brand specializes in Mediterranean products and sources ingredients from the area. Everything I've tried from this brand is decent. Anything else in the mainstream supermarkets and the price tag of £3-4 will most likely be made of low-quality oils and perhaps not even infused with real truffle at all. It is one expensive deli gourmet ingredient but it's an investment and the options are unlimited... Mash potato is just one, I'm using it in pasta sauces, omelettes and risotto too!

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