Smoked haddock & prawn cheesy rösti fish pie

Preheat the oven to 220ºC, gas mark 7. Put the röstis onto a baking sheet and bake for 10 minutes. Meanwhile, pour the milk into a large saucepan and add the haddock. Simmer for 8 minutes, until the fish is opaque and flakes easily, then lift to a plate using a fish slice.

Off the heat, add the butter to the milk in the pan and allow to melt. Gradually but vigorously whisk in the flour, then bring to the boil, stirring until thickened and smooth. Boil for 1 minute, then remove from the heat and stir in 50g cheese and all the prawns. Season.

Preheat a large saucepan over a medium heat, then add the damp spinach. Wilt with the lid on for 4 minutes, then drain and cool under cold water. Drain again and squeeze out as much water as possible using your hands.

Scatter the spinach into a medium ceramic baking dish (about 1L or 18x28cm), season, then flake in the haddock and pour over the sauce. Stir gently. Tear the part-baked röstis into chunks to cover the filling, then scatter with the remaining cheese. Bake on the hot baking sheet for 15 minutes, until bubbling, golden and crisp. Delicious served with peas, if liked.