Heat a grill. Place the steak on the grill, and cook first side 8 minutes. Turn steak and place onions on grill as well. Cook second side 8 minutes; flip onions after 4 minutes and cook until tender. Remove meat and onions to a cutting board and keep warm at least 5 minutes. Butter bread, turn off grill and place bread on grill to toast. Slice steak, and make sandwiches with grilled bread, onions and peppers; season with salt and pepper and drizzle with olive oil.
Yield: 6 sandwiches