This is quite a rich tart and when I had it in Ireland, it was served with a simple, fresh green salad. Perfect for lunch or a light dinner. The sweet, caramelised shallots with the soft, fresh fish, creamy cheeses and chives were encased in the silkiest savoury custard in a buttery, short pastry. I couldn’t eat the whole slice, it was pretty big, so I asked if I could bring it home. It was delicious cold, the next day too.
For the Pastry
First make the pastry. Pulse the flour, butter and salt in a food processor until the mixture resembles fine breadcrumbs. Beat the egg yolk with 2 tablespoons of water and pulse gradually into the dry ingredients just until the dough comes together. Wrap in baking parchment and refrigerate for 30 minutes to allow the pastry to rest.
Preheat oven to 180F (400F/Gas 6).
Remove the pastry from the refrigerator and when pliable, roll on a lightly floured surface into a circle, large enough to line a 25cm (10 in) loose-bottomed tart tin with a little overhang. Push the pastry into every ridge of the tin and then trim off the excess pastry with your rolling pin or a knife.
Line the pastry base with baking parchment and fill with baking beans.
Place on a baking sheet and set on the top shelf of the oven and bake for 15 minutes. Lift out the beans and parchment paper and return to the oven for a further 5-10 minutes until the base is dry and golden.
Turn the oven down to 170C (375F/Gas 5).
Next, make the filling. Place a frying pan over a high heat and add the spinach, season and cook until wilted. Remove from the heat, place on a large plate and allow to cool. Once cool, squeeze out the excess liquid and finely chop the spinach. Set aside.
Place the haddock in a medium saucepan with the milk, bay leaves and peppercorns. Bring to the boil and simmer for a minute before turning off the heat. Cover and set aside for 10 minutes.
Melt the butter in a medium pan and add the shallots, cook until soft but not too coloured, it may take up to 10 minutes. Add the flour and mustard powder and stir over a medium heat for 1 minute.
Strain the fish into a colander, discard the bay leaves and peppercorns and gradually stir the poaching milk into the shallot mixture. Stir constantly for 5 minutes, until the sauce thickens, ensuring there aren’t any lumps. Take off the heat and add the cheeses, yolks, chives, cream and seasoning. Flake the fish and add that too, gently stir.
Spoon the filling and the spinach into the tart case and bake for 30-35 minutes, check after 30 minutes.
