Preparation Position rack in center of oven and preheat to 350°F. Cut off and discard top quarter of each garlic head. Place garlic in small baking dish. Drizzle with 2 tablespoons oil. Cover dish with foil and bake until garlic is tender, about 1 hour 10 minutes. Cool garlic slightly. Squeeze garlic out of papery skins, letting garlic fall into small bowl. Mash with fork. Stir in butter. Season to taste with salt and pepper. (Roasted garlic butter can be made 2 days ahead. Cover and keep refrigerated. Bring to room temperature before using.) Prepare barbecue (medium heat). Brush corn lightly all over with remaining 2 tablespoons oil. Grill corn until brown in spots, turning occasionally, about 12 minutes. Serve hot, passing roasted garlic butter separately.
Preparation Position rack in center of oven and preheat to 350°F. Cut off and discard top quarter of each garlic head. Place garlic in small baking dish. Drizzle with 2 tablespoons oil. Cover dish with foil and bake until garlic is tender, about 1 hour 10 minutes. Cool garlic slightly. Squeeze garlic out of papery skins, letting garlic fall into small bowl. Mash with fork. Stir in butter. Season to taste with salt and pepper. (Roasted garlic butter can be made 2 days ahead. Cover and keep refrigerated. Bring to room temperature before using.) Prepare barbecue (medium heat). Brush corn lightly all over with remaining 2 tablespoons oil. Grill corn until brown in spots, turning occasionally, about 12 minutes. Serve hot, passing roasted garlic butter separately.