Rinse your basmati rice in at least three changes of water to wash out the starch and leave to soak in a bowl of cold water on one side for 30 mins.
Next, chop your onions in half, peel them and then slice into fine rings and dry them off in a tablespoon of oil until golden brown and set aside.
Heat a non-stick pan. Add the remaining green cardamoms, cloves, black cardamom and cinnamon along with bay leaf and caraway seeds and roast.
Add onions, carrot, French beans, cauliflower florets and green peas.
Sprinkle salt, cover and cook on medium heat for two minutes. Add ginger-garlic paste mixed with a little water and stir. Cover and cook for two minutes. Add turmeric powder, red chilli powder and coriander powder and cook. Whisk yogurt with rose water and saffron. Add a little water or milk and whisk well. Add tomato puree to the vegetables along with half teaspoon Garam masala powder and mix well. Simmer for two minutes.
Preheat the oven to 180°C/350°F/gas 4.
Meanwhile, in a separate pan you need to cook the rice and prepare the fried onions for layering. Drain the rice and transfer to a saucepan. Pour enough cold water over the rice so that it is covered by 2cm, and bring to the boil. Boil for 8 minutes, until it’s just cooked but still has a bite. Drain and set aside.
Take an ovenproof pot which will snugly accommodate the rice and veg curry, such as a casserole dish. Remove half of the veg from the veg curry using a slotted spoon (to leave the sauce behind) and place it at the bottom of the pot. Add a little of chopped mint and coriander at each layer. Top the veg with half of the rice and half of the onions and repeat with the rest of the veg, rice and onions. Keep the sauce of the curry aside to serve with the biryani. Bake the biryani for 20 mins.
Sprinkle the rice with the rose water, saffron, Toasted cashews and sliced pistachio.