Wash the rice with cool water in a large bowl. Strain it using a large colander and rinse it in cold water.
Add 14 cups of water and the salt to a 7.5-quart nonstick pot over high heat and to bring to boil. Taste the water; it should be very salty (like pasta water). Add the washed rice and mix so it doesn't stick. Cook uncovered on medium heat until it is al dente, 8 to 10 minutes.
Drain the rice in a large colander and rinse quickly with cold water. Shake the colander to remove the excess water.
Pour 1/2 cup of the oil in the same pot and heat it until hot but not smoky. Add the turmeric and swirl. Put about 1/5 of the rice back in the pot and press gently until it forms a crust at the bottom. Pour the rest of the rice back in the pot without pressing so it is fluffy. Try to pour it in the center of the pot so as it settles down it creates a hilltop in the middle. Use the end of a wooden spoon to poke 6 to 8 holes into the rice to allow for steaming.
Cover the pot and cook on medium-low heat until the rice starts steaming, 5 to 8 minutes. Open the lid, cover the pot with a clean kitchen towel to catch the moisture, then place the lid back on and cook on low heat for 45 to 50 minutes.
Add the remaining 1/3 cup oil and the drained barberries to a small skillet and saute on medium heat, 3 to 5 minutes. Add the sugar and keep mixing for a few minutes until the sugar dissolves. Turn off the heat.
Take 1 cup of cooked rice out of the pot and mix it with the saffron water; set it aside.
Pour the butter all over the remaining rice still in the pot. Place a 12-inch or larger serving platter upside down on top of the pot, hold the pot handles and the platter on both sides and with one motion flip over the pot. All the rice should fall on the platter like a cake with the crispy side on top.
Garnish with the barberries and the reserved saffron rice.
Add the saffron to 1/4 cup of room temperature water in a water glass or coffee mug, mix well. Leave it aside for 2 hours.