Using a clean coffee grinder, grind together the spices you will use to make the mansaf.
Yogurt Sauce
Place yogurt, water, cornstarch and the spice mix you just made into a blender container and whirl for about 1 minute. This thorough blending is what will keep the yogurt from curdling when cooked.
Mansaf
Turn your Instant Pot on Sauté and when it is hot, add the ghee. To the hot ghee, add the sliced onions and the lamb. Cook for 2-3 minutes, just long enough to coat the lamb and onions with the ghee.
Pour in the spiced yogurt sauce and mix well so the ghee is incorporated into the yogurt sauce.
Close the lid and set your Instant Pot to cook on the SOUP setting for 10 minutes. When it is done cooking, allow the pot to sit undisturbed for 10 minutes and then release all remaining pressure.
To serve, place the cooked rice on a platter. Arrange the meat over the rice along with some of the sauce.
Reserve any extra sauce to pass around the table. Garnish with the toasted nuts and enjoy!