However, the last time Akane is shown to be cooking is in the Shinnusuke
arc.  It begins with Akane preparing a dinner that no one wants to eat,
assuming that it will be horrible.  So she eats it herself while watching

TV

(and finding out about Ryugenzawa).  Kasumi later offers the leftovers to
the family.  To everyone's surprise, it turns out to be edible.  Ranma even
goes so far as to call it "normal".

I was under the impression that it was the magical properties of the Water
Of Life that made her cooking edible, and that wouldd account for her return
to bad cooking once the spring dried up.  The fact that it is never
mentioned again could just be because Takahashi-sama didn't want to beat a
dead horse.

-Mat