Bring a large pot of water to boil. Season with kosher salt.
Pour in rinsed, soaked basmati rice and give it a few stirs.
Rapid boil the rice for 6-8 minutes or until the rice is long grained and al-dente, but not fully cooked.
Drain and rinse once with cold water. Set aside for a moment while you prepare the base of your tahdig.
(Prepare in advance) In a mixing bowl, combine egg yolk, 2 tbsp of saffron water, a little salt and pepper, a dash of garlic powder, and a ¼ cup of yogurt until smooth.
Add 1 cup of the par-cooked basmati rice to the mixing bowl and carefully toss and coat the rice completely with the egg saffron yogurt mixture.
In a nonstick deep, and semi wide pot, turn on your heat to medium high. Once preheated, add 1 tbsp of butter, and one tbsp of olive oil to the pan. It’s helpful here to rub butter and olive oil on the edges and sides of the pot as well to prevent sticking. (Nonstick pots are always preferred for tahdig, but I have also used cast iron pots, which also work fantastic. If you do not have a nonstick pot, place a layer of parchment paper on the bottom of the pot on top of the butter/oil mixture before adding the rice yogurt saffron mixture.)
Add the rice and saffron yogurt mixture and press it into the bottom of the pan in an even layer to form a crust on the bottom.
Then layer in the rest of the par-cooked rice in a dome or mountain shape, so it comes to a point in the middle.
Using the bottom of a wooden spoon or kitchen utensil, make 3 wholes from the bottom to the top so the air can escape through while steaming the rice.
Add a drizzle of saffron water on the top and a tbsp more of some butter cubes to begin the steaming process. Put a clean dish cloth around the edges of the pot, and seal it with the lid, folding the corners of the towel inside so it’s not hanging off the side.
Cook on medium high for 5 more minutes and then lower the heat to medium low and cook for approximately 1 hour.
Remove the lid and run your spatula round the edges of the pot to separate any pieces that may have stuck to the sides. This will ensure that when you flip the pot upside down to create the tahdig, the rice will come out perfectly.
Grab a large circular platter for your rice that is bigger than the size of the pot and place it on top of the pot with oven mits.
Holding the pot by the handles and holding the platter at the same time, carefully flip the rice upside down onto platter and carefully slide it onto your countertop to slowly reveal the tahdig!
The tahdig should come out of the pot with ease and be a crispy golden-brown color. (Every tahdig is different so it’s ok if it’s a little over browned, but this can be avoided by not turning the heat on too, too high in the first 5 minutes of cooking).
Allow to cool slightly, then serve with the chicken barberry sauce and a side of cucumber, yogurt, mint sauce.