Preheat oven to 200°F. Season steaks with salt and pepper. Place rosemary sprig where each steak will be set on grill. Lay steaks over rosemary; top each with savory sprig. Close grill; cook 4 minutes for medium-rare. If grill is small, cook steaks 2 at a time. Place on rimmed baking sheet and keep warm in oven.
Remove garlic from grill; set aside to cool slightly. With drip pan underneath, slowly pour water over grill surface to deglaze, scraping with a wooden spoon to loosen brown bits.
Peel garlic cloves, then place in a sieve. With a spoon, press garlic through sieve to make a paste; place in a small bowl. Spoon off fat from cooking juices in drip pan; discard. Pour cooking juices over garlic and whisk until well blended. Transfer steaks to warmed serving plates, then drizzle with garlic sauce.
Alternate preparation: Steaks can also be done on an outdoor grill or stovetop grill pan (though there will not be pan juices for deglazing). Preheat grill. Arrange garlic cloves on a metal skewer; cook over medium heat until tender, about 10 minutes. Meanwhile, grill steaks 6 to 8 minutes, turning halfway through cooking.