Directions

1. Heat oven to 190C/170C fan/gas 5. To make the filling, heat a pan of salted water. When boiling, add potatoes and boil for 15 mins until tender. Melt the butter then fry the onions for a few mins. Add cumin, mustard seeds, ginger and chillies and fry, stirring occasionally, for about 7 mins until soft. Stir in curry paste.
2. Cook the spinach in the microwave on High for 5 mins. Drain and squeeze out as much liquid as you can, then chop it. Drain the potatoes and tip them into the spice mixture. Crush lightly to break them up into chunks rather than mash. Toss in the spice mixture with plenty of salt to coat them, then add the spinach, tomatoes and coriander.
3. Carefully unroll the pastry and brush 2 x 20cm loose-bottomed sandwich tins with some butter. Brush the first sheet of pastry and lay it in and across the tin so that it hangs over the side. Do the same with another sheet of pastry to cover the other side of the tin (so the two form a cross), butter and fold the final sheet in half and lay it in the base of the tin to create a firm base. Do the same with the other tin and remaining pastry.
4. Spoon the filling into the tin and fold up the pastry that is overhanging so that it covers the filling. Brush generously with the remaining butter and sprinkle with seeds. Bake for 35 mins until golden and crisp. Serve with a salad and mango chutney, or a raita made by mixing plain yogurt with mint sauce or jelly, if you like.