To prepare the broth: Heat the oil in a large stockpot over medium-high heat. Add the lamb shanks and sear on all sides. When the shanks are nicely browned on all sides, add 6 cups water and bring to a boil, skimming away the scum from the surface. Once you have skimmed all the foam from the surface, add the onion, spices, and salt. Reduce the heat and simmer for 1½ to 2 hours, or until the meat is very tender but not falling off the bone. To prepare the yogurt sauce: Blend 1 disc of jameed with 2 cups water in a powerful food processor until smooth, then pour into a deep saucepan. Add the plain yogurt, cornstarch slurry, 1 teaspoon salt, and 1 cup water to the pan and mix to combine. Place over medium-high heat and stir with a whisk until the yogurt boils. It is important to whisk continuously until it boils to prevent curdling. If it does curdle, use a handheld immersion blender to smooth everything together. Lower heat to a bare simmer. Heat the olive oil in a small frying pan, then add the garlic and fry over medium heat for 1 to 2 minutes, or until fragrant but still white. Pour the garlic into the yogurt, stir, and remove from heat. The sauce should be quite salty and sour, so taste and adjust seasoning as necessary. To prepare the rice: Place the butter and oil in a nonstick pot or Dutch oven over high heat. Add the drained rice, tossing to fully coat in the oil, and pour in 2½ cups water, the salt, and turmeric, and bring to a boil. Let it simmer for 2 to 5 minutes, until most of the water is absorbed, then give it one more stir, cover the lid with a dish towel, and tightly close it over the pan. The towel will absorb any rising steam. Remove the pot from the heat and let it sit for about 15 minutes, or until you are ready to assemble the dish. To assemble the dish: When the lamb shanks are done, remove and set them aside. Strain the broth (stock) through a fine mesh strainer into a large pot and discard the onion and spices. Strain the yogurt sauce through the same mesh strainer over the broth and mix to combine. The sauce should be very smooth (if it is not, this is the time to bring out the handheld immersion blender). Taste and adjust salt to your liking, bearing in mind that it should be very salty and tangy. Add the shanks to the pot and bring to a boil, then let simmer for another 15 minutes until all the flavors have melded. To serve, tear up the bread and arrange it in a large, round serving platter. Pour a ladleful of the yogurt sauce all over the bread. Spread the rice over the bread and top with the lamb shanks. Pour a few more ladlefuls of the yogurt sauce on top, enough to soak through the rice and bread. Sprinkle with the toasted almonds. Pour the remaining sauce into a serving bowl and serve alongside the rice for each person to add as much as they like over their plate or to sip as soup.