You roast them until dark brown, almost black. Like dark roasted coffee or dark chocolate. They contain caffeine like stimulants and an extraordinarily rich flavor profile.
They are related to avocados, in the Laurel or Lauraceae family, and their fruit when fully ripe can be eaten like an avocado. The leaves, although 3 times as strong, can be substituted for the European Bay Leaf, the “Bay leaves” you buy at the store, Laurus nobilis.
The edible uses of these trees and their growth were covered in my recent class, How to Eat Acorns and Bay Nuts.
California Bay Laurel trees are also involved in the phenomenon of Sudden Oak Death. Ask me how.