1.  Preheat the oven to 375 degrees F.  Without getting too fussy or breaking the heads apart, remove as much of the papery coating from them as you can.  Cut the top pointy parts off the head to expose a bit of each clove.  Drizzle with olive oil and sprinkle with salt.

2.  Film a small baking dish with a little more oil and add the garlic.  Cover with aluminum foil and bake until the garlic is soft (you'll be able to pierce it easily with a thin-bladed knife), 40 minutes or longer.

Faster roasted garlic

If you're in a hurry, break the heads into individual cloves, but do not peel them.  Spread them in a pan, sprinkle with salt, and drizzle with oil.  Bake, shaking the pan occasionally, until tender.  20 to 30 minutes.