Fish pie is my favourite of all the pies. It's a little renegade, with a fluffy mashed potato topping instead of pastry; and sure, it doesn't wrap all the way around the sides. Cheese? Cheese on top? Cheese and fish? What the...? I also complete this unholy triumvirate by having just the lightest splodge of ketchup, because any type of crisp potato, like the one up top here, demands ketchup.
I draw the line at putting hard-boiled eggs inside it though. That's just too much. Instead, I use a mixture of smoked fish, white fish and salmon, encased in a thick, rich white sauce that absolutely has to be rammed full of fragrant tarragon. If you don't like tarragon (WHY) then this is not the pie for you.
On the topping, I have experimented far and wide with this too. One particularly fun experiment was to layer very thinly sliced new potatoes, buttered liberally, so that you get a scalloped fan effect. While it looked very impressive, it lacked the comfort of mash, and this pie really is all about the comfort. I've used a mixture of normal potato and sweet potato (don't bother), and finally I tried replacing some of the potatoes with celeriac, just because I really bloody love celeriac. It worked beautifully, but if you don't like celeriac then just go full mash.
My Ultimate Fish Pie
1 small onion, sliced
1 bay leaf
5 pink peppercorns, lightly crushed
1/2 tsp coriander seed
1/2 tsp black peppercorns
1 glass of dry white wine
400gr raw mixed fish; I use a mixture of smoked haddock, hake / pollack, and salmon at a ratio of 30% / 40% / 30% - chopped in chunks
40gr plain flour
60gr butter, + 10gr butter for the mash
A small handful of parsley, finely minced
A handful of tarragon, leaves picked and finely minced, stems reserved
1/2 a lemon, zested and juiced
350gr floury potatoes, peeled and quarted
150gr celeriac, peeled and diced into small cubes
A small handful mixture of cheddar and parmesan
Bring a large saucepan to the boil and add the potatoes and celeriac, cook until tender. Drain, and leave in the colander in the saucepan off the heat with the lid off to steam some of the moisture away, for 10 minutes. Next, mash thoroughly with 10gr of butter and plenty of salt and pepper.
Meanwhile, in a small saucepan, simmer the white wine with the peppercorns, sliced onion tarragon stems, coriander seen and bay leaf, until the white wine has reduced by half. Leave to one side to cool.
In a small pan, add the milk and the fish, with a generous seasoning of salt. Bring to the boil, then remove immediately, and lift the fish out carefully with a slotted spoon, and arrange in an appropriate pie dish.
In a small saucepan, make the roux by melting the butter and the 40gr plain flour on a low heat and stirring with a balloon whisk well. When the mixture turns caramel colour and the flour has cooked out, add the wine mixture through a sieve and whisk for your life, to make sure there are no lumps. Add a ladleful of milk, whisking again, and repeat. By this point, you should have a smooth sauce and be able to add the rest of the milk in without having to whisk any more. If you have got lumps, give it a quick blitz with a handheld blender.
Preheat the oven to 180 degrees. Leave the sauce mixture to simmer gently for a few minutes; you want a thick sauce that healthily coats the back of a spoon. You may need to simmer it for up to 10 minutes to achieve this, but keep stirring with that whisk so the bottom doesn't burn.
Remove from the heat, add the lemon zest and juice, taste for seasoning. Add the tarragon and the parsley, and pour over the fish mixture. Next, using either a piping bag if you can be arsed or a spoon and fork, distribute the mash over the pie mixture; the sauce should be thick enough that the mash doesn't sink. Sprinkle the cheese over the top; at this point the pie can cool down and go in the fridge or freezer to cook later, if you like. Bake for 20 - 25 minutes, until the top is nicely golden and the cheese has melted. Leave to stand for 5 minutes before serving, and serve with buttered steamed peas and a sploge of ketchup.