After spending a day working with both Ricettario and Gary's cookbook, I unfortunately have to say that neither is a very useful tool and both are extremely buggy.
Ricettario is very limited, without a searchbot and only allowing a fixed (14) ingredients.
Gary's cookbook is horribly buggy. In version 2.3.3 the frontend editing just straight up doesn't work. In 2.3.4 the frontend editing strips any line feed formatting destroying the readability of your content. The forums are in German only so don't expect any help there (unless you happen to speak German).
Anyway, I'm not trying to complain, just hoping to prevent someone else from wasting a day if they are looking for a finished GPL component.
I'll likely end up with a non joomla php/sql GPL script from sourceforge or something.