Combine coriander, cumin, fennel, cardamom, cloves and pepper. Saute in a dry skillet for 2 minutes. Remove and let cool. Grind in a coffee grinder or mortar and pestle. Sprinkle this mixture over the meat along with the salt. Let marinate for at least 20 minutes up to 1 day. Saute meat in ghee for 5 minutes. Add onion and saute fo 5 minutes. Add garlic, ginger and lemon grass. Saute for 2 minutes. Add cinnamon, bay leaves and stock. Bring to a boil, add potatoes and simmer for 45 minutes. Add yogurt and simmer (Do not Boil) for 20 minutes. Season with salt and pepper and serve over rice.