Trim the excess fat and sinew from the meat, and cut it into 2.5 cm
cubes.
Place the coriander, cumin, mustard seeds, peppercorn, chili 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 1 minute.
Add the meat and cook. Stirring until it is coated with the spice
paste.
Add tomato paste and stock.
Simmer, cover, for 1 hour 30 minutes, or until the meat is tender.