Combine lamb, yogurt, vinegar, half the garlic and half the ginger in large bowl;
mix well. Cover, refrigerate 3 hours or overnight. Heat ghee in large pan, add whole spices;
cook, stirring, until fragrant. Add onions and remaining garlic and ginger; cook, stirring, until onions are browned lightly.
Add ground spices; cook, stirring, until fragrant. Add lamb mixture, stir to coat in spice mixture.
Add stock; simmer, covered, for 1 1/2 hours. Remove cover; simmer about 30 minutes or until lamb is tender.
Just before serving, stir in garam masala and fresh herbs; heat through.