Slice the tops off the heads of garlic, drizzle with a little olive oil, and wrap tightly in aluminum foil. Bake in 350F (180C) oven for 45 minutes to 1 hour. Remove from oven and let cool. When cool, squeeze the garlic out of the 'paper' shells. Add this to the olive oil in a large saucepan (you can also add the 'paper'). Heat the olive oil (not very hot, but more than warm) to extract the flavor from the garlic. Let cool. Letting it steep for a couple of days will intensify the flavor. Strain through several layers of cheesecloth or through a tightly woven dish towel. Using a funnel return the oil to the bottle it was bought in, or put into a decorative bottle and keep next to the stove. Tip: save the garlic after you have strained the oil. It is lovely in sauces, soups, or just spread on toast.