Adjust oven rack to center position and preheat oven to 350 degrees F . Remove 4 cloves garlic from head and set aside. Place remaining head in the center of a sheet of aluminum foil. Drizzle with 1 tablespoon olive oil and season with salt. Wrap tightly with foil and place in an oven-safe cast iron, carbon steel, or stainless steel skillet, then transfer to oven. Roast until garlic is completely tender, about 1 hour. Remove from oven and refrigerate until ready to use the next day.
