Preheat the grill to medium-high heat.
In a small bowl, combine the olive oil, garlic, rosemary, thyme, salt, and pepper.
Place the steaks in a shallow dish and pour the marinade over them. Turn to coat evenly and let marinate for 15 minutes.
.Heat the butter in a large skillet over medium-high heat. Add the onions andcook, stirring occasionally, until the onions are golden and starting tocaramelize, about 10 minutes.
Place the steaks on the preheated grill and cook for 8 to 10 minutes, flipping once, until the steak is cooked to your desired doneness.
Serve the steak with the caramelized onions. Enjoy!