[tsimionescu]

While recipes are not copyrightable, they are not automatically public either. A restaurant can consider its recipes trade secrets, and sue any employee that discloses them and win. Even photographing the chef's recipe book or something as an outside person would be punishable via trade secret laws. Famously, Coca Cola's recipe is supposed to be a closely guarded secret, for example.

So, while of course there are many widely known and available tiramisu recipes, a specific recipe from a specific restaurant is not necessarily so. Just in passing, this is something that many people who wish for an end to software copyright forget: the alternative to copyright is not at all free public software, it is trade secret Linux "recipes".