Heat oven to 400º and heat grill for medium-high indirect heat with coals on one side.
Finely chop the leaves of 2 sprigs of rosemary and transfer to a mortar along with 2 teaspoons of kosher salt. Crush with a pestle and add 2 tablespoons olive oil as you continue to crush to form a thin paste. Set aside. If you do not have a mortar and pestle, simply put the rosemary, salt and oil in a small bowl.
Meanwhile, roast garlic by cutting the top 1/4 inch off of the garlic bulb to expose the cloves. Place on a piece of foil, drizzle with a little olive oil and wrap loosely. Roast in oven for 30 minutes. Unwrap the foil and continue to roast for 10 more minutes until cloves look brown and caramelized. Remove from oven and set aside.
As the garlic is roasting, prepare the grape tomatoes. Place tomatoes on a small sheet pan. Toss with 1 tablespoon of olive oil and 1 teaspoon kosher salt. Roast in the top third of the oven for 12-15 minutes until the tomatoes begin to brown and just start to split. Remove from oven and set aside.
Rub a small amount of the rosemary-oil mixture, about 1 teaspoon, over both sides of the steak. Grill on the hot side of the grill over the coals, for 6 minutes. You may need to move steak away from direct heat if flare-ups occur, then return to direct heat to continue. Turn steak on its side with tongs to grill the edge, holding for about 2 minutes. Turn steak over to the other side and grill for about 5 to 6 minutes until medium-rare. The internal temperature should be 120º when using an instant read thermometer. Steak should feel springy to touch. Transfer to cutting board and immediately spread 1 tablespoon of the rosemary-oil mixture over the top of the steak. Allow to rest for 10 minutes before carving.