Heat the oil in a large pan set over a medium heat. Add the chopped leek and fry for a few minutes to soften. Stir in the curry powder, half of the curry leaves and the flour, and cook for one minute. Add the coconut milk, a little at a time to begin with, mixing into the flour to make a smooth sauce, before adding more. Bring to a gentle simmer and season the sauce well.

Turn off the heat and add the fish pie mix, prawns, sweetcorn and a squeeze of lime juice. Spoon the mixture into a baking or pie dish.

Heat the oven to 200C/180C fan/gas 6. Unwrap the filo and remove one sheet, keeping the rest covered with a tea towel to prevent it from drying out. Brush the sheet with a little oil and scrunch it into a loose ball, then place it on top of the pie filling. Continue with 5 more sheets of pastry (if cooking for four), until the top of the pie is covered. Rub the remaining curry leaves in a little oil and poke them into the dips in the pastry (skip this stage if you have been delivered or bought dried curry leaves). Sprinkle the top with nigella or black onion seeds.

Bake in the centre of the oven for 30 mins, until the pastry topping is golden and crunchy. Serve with salad.