Today is the big day: got the garlic, got the oil, got 2 stoneware roasters, one with hole, one without. Let's give this a whirl.
I started by removing all the paper skin that I could without disassembling the head. Then I cut off the pointy tips (not the root end!)
Then I put a teaspoon of water into the bowl of each garlic roaster, and placed the garlic root side down into it. I drizzled some olive oil over it (I just used the cheap, pale kind; you may want to use extra virgin) and covered it. I place the roasters in a cold oven, turned it up to 400°, and let it roast for 45 minutes.
There was not a great deal of difference between the two, but I think the one without the hole was easier to wash - the garlic didn't bake onto the dish. Also, bonus: roasted garlic is amazing! I thought it was just like regular garlic only soft and spreadable, but it's not! It's much milder, nutty and almost sweet.
One of these heads we spread on bread to enjoy; the other I mixed with some olive oil, lemon juice, and parmesan cheese and dressed some pasta & greens with it.
For the potters: the roaster is thrown in 2 parts: the bowl is a shallow dish with a gallery for the lid to rest on, and took about a pound of clay; the lid was thrown as a deep bowl whose rim matched the outer edge of the gallery (you'll need calipers.) It required about 1.25 pounds of clay. At leatherhard the lid is trimmed to a smooth dome & the knob is added. They are fired together during both the bisque and the glaze firings.