Soak the burghul and dhals overnight.
Soak burghul and dhals together overnight in a large bowl with enough water to cover. Rinse under running water, drain and place in a large heavy-based saucepan with lamb, garlic and ginger, then cover with 1.5 litres water. Bring to the boil, skimming any impurities from the surface, then reduce heat to low and cook for 2 hours or until lamb is meltingly tender. Using tongs, transfer meat to a large plate, reserving dhal in cooking liquid. When cool enough to handle, remove bones from lamb and discard. Finely chop lamb and set aside.
Heat ghee in a large saucepan over medium heat. Add saffron and spices, and cook for 1 minute or until fragrant. Add reserved dhal mixture and lamb. Reduce heat to low and cook, stirring occasionally, for 10 minutes or until heated through.
Meanwhile, to make fried onions, heat ghee in a frying pan over medium heat. Add onions and cook, stirring occasionally, for 8 minutes or until golden. Drain on paper towel.
Top haleem with fried onions, coriander, mint and chilli, and serve immediately with lemon wedges on the side.