Trim the steaks of fat and gristle. Rub the steaks on both sides with 1 tablespoon of the oil. Put them on a rack over a broiler pan. Broil steaks 3 to 4 inches from heat 3 minutes on the first side; sprinkle with half of the salt and pepper, turn.
Broil on second side 4 more minutes; sprinkle with remaining salt and pepper. Remove to a hot platter. While steaks broil, heat 2 tablespoons of the oil in a skillet. Saute the peppers, stirring often, until they are heated through, about 5 minutes. Remove to platter with steaks. Heat the last tablespoon of oil and butter in skillet. Saute garlic and parsley, spoon over steaks.