Osso Buco

12 pieces veal osso buco (2.5kg)
¼ cup (35g) plain flour
¼ cup (60ml) olive oil
40g butter
1 medium brown onion (150g), chopped coarsely
2 gloves garlic, crushed
3 trimmed celery stalks (300g), chopped coarsely
2 large carrots (360g),chopped coarsely
4 medium tomatoes (600g),chopped coarsely
2 tablespoons tomato paste
1 cup (250ml) dry white wine
1 cup (250ml) beef stock
400g can crushed tomatoes
3 sprigs fresh thyme
¼ cup coarsely chopped fresh flat leaf parsley

1 tablespoon finely grated lemon rind
1/3 cup finely chopped fresh flat leaf parsley
2 gloves garlic, chopped finely
Coat veal in flour, shake away excess flour. Heat oil in large casserole dish, cook veal, in batches, until browned
Melt butter in same dish, cook onion, garlic, celery and carrot, stirring until vegetables soften. Stir remaining ingredients
Return veal to dish, fitting pieces upright and tightly together in single layer, bring to the boil. Reduce heat, simmer, covered, 1 ¾ hours. Uncover, cook for further 30 minutes.
Remove veal from dish, cover to keep warm. Bring sauce to the boil, uncover for 10 minutes or until sauce thickens slightly
Meanwhile combine ingredients for gremolata in a small bowl
Divide veal among serving plates, top with sauce, sprinkle with gremolata. Serve with mashed potato.