Rinse the rice in several changes of water
to remove excess starch, then put in a bowl
of cold water and leave to soak for 30 mins.
Meanwhile, fry the onions in the oil for
8 mins until soft and starting to colour. Add
the ginger, then cook for 2 mins more. Stir in
the curry paste followed by the whole spices,
cook for 1 min more, then tip in the potatoes
and cauliflower. Pour in 300ml water, cover
and boil for about 5-7 mins until the veg are
just tender, but still have a little resistance.
Stir in the yogurt and peas with 1 tsp salt.
Mix the saffron, rosewater and 3 tbsp
boiling water together and stir well. Drain the
rice, tip into a pan of boiling salted water,
then cook for 5 mins until almost tender.
Drain again. Get out a large ovenproof dish
with a lid and butter the base. Tip the curry
sauce into the base, scatter over the nuts,
then spoon over the rice. Drizzle over the
rosewater mixture, then cover with foil
followed by the lid. Can be chilled overnight
until ready to cook.
Heat oven to 180C/fan 160C/gas 4. Put
the biryani in the oven for 45 mins-1 hr until
thoroughly heated through. To check it’s
ready, try a spoonful from the centre of the
rice. For the garnish, slowly fry the onions in
the oil until really golden and crisp (this can
be done in advance). When the biryani is hot
and ready to serve, gently toss through the
onions and coriander.