Preheat the oven to 350°. Season the garlic with salt and pepper. In an ovenproof skillet, melt 2 tablespoons of the butter. Add the garlic cut side down. Add the stock and bring to a simmer. Cover and roast until tender, about 30 minutes.
Set the skillet over moderate heat. Simmer to evaporate the stock. Add 1 tablespoon of the butter; cook until the garlic is browned. Transfer the garlic to a plate.
In each of 2 large skillets, heat 1 tablespoon of oil. Season the steaks, add them to the skillets and sear over high heat for 2 minutes. Cook over moderately high heat, turning once, until the steaks are medium-rare, about 6 minutes; transfer to plates.
Pour half of the wine into each skillet and boil. Scrape the juices from 1 skillet into the other; boil until reduced by half. Add the water and boil until reduced by half, 5 minutes. Off the heat, swirl in the remaining butter. Season with salt and pour over the steaks. Garnish with the garlic and serve.