First of all sift the flour with the pinch of salt into a large bowl, holding the sieve up high to give it a good airing. Then add the lard and butter and, using only your fingertips, lightly and gently rub the fat into the flour, again lifting the mixture up high all the time to give it a good airing. When everything is crumbly, add the Parmesan and then sprinkle in some cold water – about 1 tablespoon. Start to mix the pastry with a knife and then finish off with your hands, adding more drops of water till you have a smooth dough that will leave the bowl clean. Then pop the pastry into a polythene bag and let it rest in the refrigerator for 30 minutes.
Meanwhile, pre-heat the oven to gas mark 5, 375°F (190°C) and pop the baking sheet in to pre-heat on the centre shelf.
After that, roll the pastry out into a circle on a surface lightly dusted with flour, and as you roll, give it quarter turns to keep the round shape, rolling it as thinly as possible. Now transfer it, rolling it over the pin, to the tin. Press it lightly and firmly all over the base and sides of the tin, easing any overlapping pastry back down to the sides, as it is important not to stretch it too much. Now trim the edges and press the pastry up about 1/4 inch (5 mm) above the rim of the tin all round. Then prick the base all over with a fork and, after that, brush some of the beaten egg for the filling all over the base and sides. Now place the tin on the baking sheet and bake it for 20-25 minutes or until the pastry is crisp and golden. Check halfway through the cooking time to make sure that the pastry isn't rising up in the centre. If it is, just prick it again a couple of times and press it back down again with your hands.
When the pastry is cooked, remove the tin from the oven and lower the temperature to gas mark 3, 325°F (170°C).
For the filling, put the haddock and kipper in a medium-sized saucepan, along with the milk, bay leaf and mace. Now bring it up to simmering point, cover with a lid and poach gently for about 2 minutes, then remove the fish from the milk. Discard the bay leaf, but reserve the milk.
Then lightly whisk the eggs and egg yolks together with a seasoning of black pepper and nutmeg, but no salt, as the fish will be fairly salty. Then heat the reserved milk, whisking in the crème fraîche or double cream. Then, when it has come to simmering point, pour it over the beaten eggs, whisking well. Now divide the cooked haddock and kipper into flakes about 1/2 inch (1 cm) in size and arrange them in the cooked pastry case, along with the smoked salmon trimmings. Next scatter the capers and gherkins all over and slowly pour half the cream and egg mixture in, allowing the liquid to settle between each addition. Then place the baking sheet in the oven, gradually add the remainder of the filling and cook for 30-35 minutes or until the surface is golden brown and feels firm in the centre.
When you have removed it from the oven, let it rest for 10 minutes, then ease it away from the edges using a small knife and place it on a suitable-sized jar, which will allow you to carefully ease the sides away. Then slide a palette knife or wide fish slice underneath and ease the tart carefully on to a plate or board ready to serve, or simply cut it into portions straight from the tin base.
