Combine the Herby Butter ingredients and store in the fridge until ready to serve.
Heat the grill or a pan to maximum, a cast iron ridged pan gives excellent results. Place the steaks in a shallow dish and the peppers in a bowl. Mix together the oil, vinegar, salt and black pepper. Set aside half this mixture to dress the salad. Spoon the remainder over the steaks and peppers.
Add the peppers to the pan and cook for a couple of minutes on each side. Remove from the pan and set aside while you cook the steaks.
Add the steaks to the hot pan – do this in two lots if the pan is over-crowded. Cook for 2 minutes on each side, then reduce the heat and cook for another 2-4 minutes, depending on how you like your steak cooked. Remove from pan and keep warm.