Make stock: Put lamb bones, ginger, onions & water in stock pot. Bring to boil, reduce heat & simmer for 2 hours, reducing liquid by half. Skim froth. Shred lamb meat. Add meat, salt, sugar & light sherry to stock. Simmer for another 20 minutes. Finish soup: Wash & soak "cloud ears." Soak noodles for a few minutes until soft. Drain & rinse mustard green; slice into shreds. Rinse bean sprouts. Wash & remove roots from scallions; shred on bias, greens & all. Prepare Fire Pot: Heat charcoal briquettes. When they start to turn white, transfer to bottom of Fire Pot; place pot on heat-proof tile on your table. Add half the broth & half the other ingredients, reserving the rest for later in dinner. Serve after broth has boiled briefly.