With a sharp knife, cut off the top of the garlic head. Cut enough off that you can see the exposed tops of the individual cloves. Discard the top. Drizzle a tablespoon or two of good quality olive oil over the top of the head of garlic, covering the exposed ends of the cloves. Place the garlic in an oven safe small casserole dish. Cover tightly with two or three layers of foil.
Bake in the oven for 45–60 minutes, depending on the size of your garlic heads. Remove dish from the oven and let cool completely so you don’t sizzle the prints off the tips of your fingers. Unwrap and squeeze the garlic cloves right out of the papery skins.
Smash up the garlic a bit and place it in the olive oil along with the bay leaf, rosemary, and peppercorns, and store in a glass jar in the fridge. Use within a week.