Preheat the oven to 175°C (347°F). In a roaster, brown the roast veal all over in 3 tbsp of hot olive oil. Remove, and brown the vegetables, half the garlic and the tomato purée in the same oil for approx. 3 minutes. Dust with flour, brown briefly then return the roast veal to the roaster. Add the veal stock and stir in the Italian herbs. Cook in the oven for approx.2 hours with the lid on. Keep adding sauce and turning the veal.
Remove the roast from the roaster and keep warm in the switched-off oven. Pass the veal stock through a sieve into a pan. Stir in the olives and bring to the boil. Season the sauce with salt and pepper.
Heat the remaining oil in a frying pan and cook the mushrooms for approx. 5 minutes. When the mushrooms are nicely browned, stir in the remaining garlic and fry briefly. Then stir in the parsley and season the mushroom mix with salt and pepper. Cut the roast into slices, arrange on plates with the olive sauce and mushrooms and serve with tagliatelle, for example.