Wash the basmati rice thoroughly and soak it in water for 1 hour. Drain and keep aside.
In the meantime, wash the fish slices and marinate with salt, black pepper and lemon juice for a minimum of 15 minutes.
Preheat the oven at 232 degrees celsius .Slice one large onion thinly. Spread it on a baking sheet and place this in the middle rack of the oven.
Bake it for approximately 20 minutes or until it turns golden brown in colour. Make sure to flip the onions in between this time period.
Grind together all the ingredients listed under "ingredients to grind" into a smooth paste. Keep this aside.
Next arrange the fish in a single layer on a baking sheet. Broil the fish for 2 minutes on each side. Note that the fish should only be half-cooked. Keep aside.
Take a cooking bowl, pour 12-15 cups water and bring it to a boil. Add to it the soaked rice, salt, cardamom, cloves, cinnamon, bay leaf and salt.
Let it cook until the rice is al-dente, this could be around 10 mins. Turn off the flame, drain the rice completely, mix in the saffron threads. Keep aside.
In a sauté pan, heat one teaspoon oil. Add in chopped onions and sauté until they turn slightly golden in colour.
Add in the chopped tomatoes, and sauté until they are wilted.
Next add the garam masala powder and sauté for a couple of seconds. Now add the ground paste, dill leaves and let it cook for 2-3 mins.
Now add in the grilled fish slices, water and cook until the fish is completely cooked. Turn off the flame.
Take an earthen pot/ regular pot layer the fish curry and the rice, starting with the fish curry and ending with the rice.
Top it with fried onions and some sprigs of dill or coriander leaves.
Cover the pot with a piece of aluminum foil, sealing the edges. Place the lid of the handi( pot) on top.
Now place this handi on a tawa ( griddle) and let it cook for 15 mins on very low flame.
Just before serving, mix it gently. Be careful as the fish pieces may break.
Serve hot with raita, onion slices or any other salad of your choice.