Begin by washing the burghul/cracked wheat thoroughly in a fine mesh sieve under cold running water until water runs clear. Place in a large bowl, cover with just-boiled water, and set aside to soak for 20 minutes.
While the burghul/cracked wheat is soaking, prepare the filling. Heat the ghee in a pan over medium-high heat. Add the onion and cook until lightly golden and translucent, about 5 minutes. Add the beef, breaking it up with a spoon until it starts to change color. Stir in the spices and salt, continue to cook until beef is nicely browned, about 10 minutes. Finally, stir in the raisins and pine nuts and remove the pan from heat. Leave to cool completely before using.
Now, for the crust: Place the onion in a food processor and pulse until finely minced. Drain the burghul/cracked wheat well, squeezing out as much liquid as possible. Add it to the food processor, along with the beef, salt, and spices. Process until the mixture is smooth and everything is well combined. It should resemble a thick paste.
Preheat your oven to 350 F (180 C). Grease a medium-sized baking tin generously with ghee. Spread half the crust mixture onto the bottom of the tin, smoothing out evenly with the back of a spoon. Top with the filling mixture, spreading it almost to the edges, leaving about a 0.4-0.8 inch border. Top with the remaining crust mixture, spreading carefully till the edges so that the entire surface is covered. Smooth out with the back of a spoon. Using a sharp knife, score the top into slices (any size/pattern you like) and press some pine nuts into the surface to decorate.
Place the whole tin onto a baking sheet lined with baking paper or foil to catch any drippings. Bake in the oven for 50-60 minutes, until deep golden brown all over. Mix the yoghurt with the sumac and parsley and serve alongside if desired.