Wash and drain the marrow bones. Grind all the ingredients mentioned under 'For the Masala' to a coarse paste using a little water. Apply this paste to the meat and transfer everything to a pressure cooker. Place the marrow bones at the bottom so that they don't bob up.
Add the finely chopped onions & the quartered tomatoes and about 5-6 cups of water (depending on how thick/clear you wish your soup to be). Adjust salt to taste (remember you have already added salt to the marinade)
Pressure cook on a full heat for about 20-25 mins or till the meat is tender. Garnish with chopped coriander, ghee and ginger julienne and serve piping hot with croutons/garlic bread/baguette slices or plain bread.