Wash Basmati rice under cold water, then soak for one hour in cold water, allowing water to come 3-4cm (1-1.5in) above the rice (the rice will expand in water, so you want some extra water in the bowl to prevent the rice from drying out).
In the meantime, prepare the saffron water – combine saffron powder and 2tbsp boiling water and set aside.
After the rice has soaked for one hour, place a heavy-base pot (see Notes above) on the stove on high heat, adding 2L of boiling water.
Once the water starts bubbling, discard cold water from the rice and carefully transfer rice to the pot.
Decrease the heat to medium-high and allow the rice to boil for 10-13 minutes. At the 10-minute mark, take a grain and if it looks parboiled and easily breaks between your finger and thumb, remove from the flame (cooking times vary for certain types of rice; be sure to check the rice every few minutes so it doesn’t overcook).
Drain the rice through a fine mesh colander and working very quickly (you don’t want the rice to sit for too long), rinse your pot and line it with parchment paper. Some of the parchment paper should come up the sides of the pot.
Add oil and saffron water in the pot and add a few serving spoons of rice at a time to coat with the oil and saffron water. With your hands, keep combing rice with the oil and saffron water so that you form an even layer of saffron-infused rice of approximately 2cm (3/4 of an inch) thickness. This will transform into the tahdig or the saffron crust we are looking for.
With a serving spoon, add the rest of the rice on top of the saffron-infused rice layer, without stirring it.
Sprinkle 100ml (a little less than ½ a cup) of cold water on the rice. Then place a tea towel or paper towel between the lid and the pot to prevent the steam from escaping. Remember to secure the tea cloth corners on top of the pot’s lid.
Turn your burner to high heat and when it is ready, place pot on top for exactly 60 seconds. This will shock the rice and start the formation of the crust.
After 60 seconds, immediately turn the heat to medium-low. (Note: If you are using an electric burner, remove the pot from the burner at the 60-second mark and place it back once the burner has reached the desired temperature.)
Allow the rice to cook for 20 minutes.
At the 20-minute mark, check the crust. With a fork, carefully lift a bit of the bottom crust from the side of the pot, you will see a vermillion crust if it is ready. If you feel it isn’t crunchy enough, cover with the lid again and let it cook for another 7-10 minutes.
When ready, remove the pot from the burner and allow it to rest for 10 minutes, then decant and serve, adorning the white rice with the vermillion pieces of the saffron crust rice on top of the snow-white rice.