1.Using mortar and pestle, coarsely crush combined seeds, salt and pepper. Stir in oil, and rub mixture all over veal.
2.Cook veal and mushrooms on heated oiled grill plate (or grill or barbecue) until browned both sides and cooked as desired.
3.Meanwhile, combine butter, parsley, garlic and mustard in a small bowl.
4.Divide rocket between serving plates; top each with mushroom, veal, then butter.