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.
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.
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.
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.