Ingredients

Step by step

1. For the shortcrust pastry, sift the flour into a large bowl with a pinch of salt and rub in the butter until it resembles breadcrumbs. Stir in enough double cream to bring the pastry together into a ball with your hands. Flatten into a disc, wrap and chill for at least 1 hour.
2. Let the pastry rest at room temperature for 15 minutes or until easier to roll out. Flour your work surface and roll the pastry disc to a circle of around 30cm diameter. Use to line a deep 23cm loose-bottomed tart tin, prick the base and chill for at least 30 minutes or until firm.
3. Preheat the oven to 200°C, fan 180°C, gas 6. Put the milk, onion, spices and bay leaf in a pan and bring slowly to the boil. Place the smoked haddock in a large heatproof bowl. Once the milk has reached boiling point, pour it over the fish, cover with a plate and set aside – the fish will poach gently as the milk cools.
4. Line the chilled tart case with baking paper and fill with baking beans. Put onto a baking tray and bake for 25 minutes until golden. Remove the paper and beans and bake the pastry for a further 5 minutes until crisp and dry, then set aside. Turn off the oven if prepping ahead.
5. Once the haddock is cool, remove it from the milk using a slotted spoon and flake into chunky pieces. Strain the milk into a large jug, discarding the onion and bay leaf.
6. Melt the butter in a medium pan, add the flour and cook for 1-2 minutes, stirring. Remove from the heat and gradually add the infused milk. Return to the heat and cook, stirring continuously, until the sauce has thickened; simmer for 2 minutes. Remove from the heat and stir in most of the grated cheese (reserving some for the top). Gently fold through the smoked haddock and most of the chives, then season. If preparing ahead, cool and chill the filling until ready to bake the tart.
7. When ready to bake, heat the oven to 220°C, fan 200°C, gas 7. Spoon the filling into the tart, scatter over the reserved cheese and bake for 25-30 minutes (or about 35 minutes from chilled), until golden brown and slightly puffy; the filling will be quite wobbly. Leave to rest and firm up for at least 30 minutes before slicing. The filled tart can be baked a day ahead; remove from the fridge for about 2 hours and serve at room temperature.
8. Bring a small saucepan of water to the boil. Carefully lower in the egg and boil for 10 minutes before plunging it into iced water to cool. Peel the egg, then finely grate it over the tart and scatter over the rest of the chives. Serve the tart in slices with dressed watercress leaves.