Preheat the oven to 350ºF.
Cut off the top of the garlic head. That’s the part with the long, thin garlic neck, not the flat root bottom. Don’t take too much of the top, just enough to expose the cloves.
Place the garlic heads into a small baking dish cut side up. You can use aluminum foil if you don’t have a baking dish. Brush or pour the olive oil over the exposed garlic heads and season with salt and pepper.
Cover the dish with its top if it has one or just use some aluminum foil. If you are only using aluminum foil, be careful not to poke any holes in it or the oil can get messy.
Transfer the garlic heads to the oven and roast for 35 to 45 minutes.
Remove the garlic from the oven and let it cool. When it is cool enough to handle, squeeze the bottom of the heads and the garlic will ooze out the cut tops.
Remove all the garlic from the cloves and either use a blender to puree or just use the side of a chefs knife to smash the cloves into a puree. Be very careful not to cut yourself.
To store, add puree to container that you can tightly cover, think glass jar, and refrigerate for up to a week.