Heat the grill/pan to maximum, a cast iron ridged pan gives excellent results.
Place the steaks in a shallow dish, and place the prepared vegetables in a bowl.
Mix together the oil, salt, black pepper and balsamic vinegar. Pour half the mixture over the steaks and the remainder over the vegetables, mix well.
Place the steaks on the grill pan and cook for 2 minutes, then turn to sear the other side. Leave to cook for two minutes before turning again. Continue to cook, allowing a total of 3-6 minutes on each side, depending on how thick the steak is and how you like it cooked.
Remove to a plate and keep warm while you cook the vegetables.
Place the vegetables on the hot pan and cook for 4-5 minutes. Serve with stir fry potatoes, if you want.