Wash and rinse the rice with cold water until the water runs clear. Soak the rice in 6 cups of cold water, add 6 tablespoons of salt and set aside for a couple of hours. Drain but don’t rinse the rice. Make sure that you don’t use your hand or a utensil during this process, as basmati rice is very delicate and can easily break.
In a large non-stick pot, add 6–8 cups of water and 2 tablespoons of vegetable oil, and bring to a boil. Add the drained rice and lentils to the boiling water; cook them for about 7 minutes until the rice is parboiled or al dente—the grain needs to be soft from the outside and firm in the centre. Drain the rice in a colander and reserve on the side.
On medium–high heat, melt some of the butter. Add a layer of sliced potatoes on the base of the pot. Gently add the parboiled lentils and rice over the potatoe, then pull the rice from the side to the centre of the pot in the shape of a dome. Make three holes in the layers of the rice with the handle of a spatula or wooden spoon - this allows the steam to circulate when cooking to ensure that the rice fully cooks through.
In a small cup mix half a cup of hot water with 3 tablespoons of butter and a pinch of saffron, and sprinkle the mixture over the rice. Once the rice starts to steam, wrap the pot lid with a towel and then reduce the heat to low (this absorbs all the excess condensed liquid and allows the rice to become fluffy);cook for about 45–50 minutes.
In a medium-sized pot, on medium heat, sauté the onions with a drizzle of vegetable oil until golden. Add the minced meat and season with cardamom powder, coriander powder, cumin powder, cinnamon powder, turmeric powder, black pepper powder, salt, a pinch of ground saffron and rose water. Cook until the meat is browned.
To prepare the garnish, deep-fry the onions in a medium-sized pot until they are crispy and golden brown. Keep aside. In a small saucepan, melt the butter and sauté the raisin and Bam dates until it has softened. Season with a sprinkle of cinnamon powder and keep to the side.
Serve the rice on a large platter, top with the minced beef mixture and garnish with dates, raisins and crispy onions.