In a medium saucepan, combine the dried oregano, crumbled bay leaves, fennel seed (if using), fresh thyme sprigs, fresh rosemary sprigs (if using), crushed red pepper flakes, and olive oil.

Heat the mixture slowly over low heat until the herbs and chiles begin to sizzle (less than 220 degrees F).

Turn off the heat when sizzling starts.

Cover the saucepan and allow the mixture to cool completely.

Pour the cooled oil into a clean, sterilized bottle.

Cover the bottle tightly.

Let the oil stand in a cool, dark place for one week before using.