Persian Tahdig Rice - saffron threads

Method

• Grind saffron threads with sugar in a mortar and pestle. Transfer to a bowl and dissolve in boiling water. Set aside to soak.
• Wash starch from the rice by rinsing it in a nonstick 4-quart pot. Rinse 3 or 4 times in lukewarm water until water runs clear. Fill the pot 3/4 full with cold water, covering the rice. Bring to a boil. Add olive oil and cook until rice is soft on the outside and still crunchy in the middle, 10 to 15 minutes.
• Drain rice and rinse with cool water. Set aside. Rinse any excess rice starch out of the pot.
• Melt butter in the clean, dry pot. Mound rice over the butter; add enough water to reach 1/3 of the height of the rice. Sprinkle salt over the rice. Wrap the lid with a kitchen towel and cover the pot to seal tightly. Simmer over medium heat until all water is absorbed and a crispy crust starts to form on the bottom, about 10 minutes.
• Fluff the rice with a fork while turning it out on a plate. Measure 1 cup rice and mix with the saffron water. Scatter saffron rice over plain rice. Detach the layer of crust, or 'tahdig', from the bottom of the pot and serve in a separate dish as a special treat.