As a patent attorney, that simple one-word answer to the question of "Can you patent a recipe?" is the bane of my existence.  The question shouldn't be "Can you patent a recipe?" but rather "Is it worth patenting arecipe?"  The answer to the former is "Yes" and the answer to the latter is almost always "No". In fact, it's been done!  See here for a brief discussion of current chefs patenting recipes, and here for a toaster cookie recipe that I use as an example when I'm training engineers or other lawyers about patents. 

But that doesn't mean it's a good idea for your everyday chef.