Ingredients

1/2 cup olive oil
1/4 cup red wine vinegar
2 tablespoons balsamic vinegar
4 cloves garlic, minced
1/4 cup diced onion
2 tablespoons chopped fresh rosemary
salt and black pepper
3 lbs sirloin steak (1 1/2″ thick)

Directions

Mix together all ingredients in a plastic bag and add steak.Refrigerate and marinate for 4 to 8 hours, flipping the steaks occasionally.Remove steaks from refrigerator 30 minutes before grilling.Drain and discard marinade from steaks.Grill over medium heat until steaks reach your desired doneness.Remove from grill and let rest for 10 minutes before slicing and serving.