Mix 2 tbsp of olive oil, the garlic, rosemary, lemon zest and salt. Brush this mixture over the veal chops. Cover and refrigerate.
Toss the onion rings with the shitake mushrooms and 2 tbsp of the oilve oil. Season, then barbecue or grill the mushrooms and onions over a medium heat for 10 mins, turning once, until tender.
Leave to cool, then roughly chop and transfer to a bowl. Add the tomatoes, thyme, parsley, vinegar and 1 tbsp of oilve oil. Remove the chops from the marinade and barbcue or grill over a medium heat for 12-15 mins, turning once. Leave the meat to rest for 5-10 mins, then serve with the grilled mushroom relish.