Trim the excess fat and sinew from the meat, and cut into 2.5 cm cubes.
Place the coriander, cumin, mustard seeds, peppercorn, chilli powder, turmeric, salt, garlic and ginger in a small bowl. Stir to combine. Add the vinegar and mix to a smooth paste.
Heat the oil in a large pan, add the onion and cook over medium heat until just soft.
Add the spice paste and stir for one minute.
Add the meat and cook, stirring until it is coated with the spice paste.
Add tomato paste and stock.
Cover and simmer for 1 1/2 hours, or until the meat is tender.