Got coffee grounds? You're on your way to this fresh and filling steak dinner.
In bowl, mix oil, herbs, scallions, vinegar, and garlic; season sauce. Rub steak with coffee; season. Grill steak over medium heat to desired doneness, about 4 minutes per side for medium-rare. Season potatoes; grill until tender, 5 minutes per side. Drizzle steak with sauce. Serve with potatoes.