The vet recommended a new kind of cat food and I had all kind of visions of horror. Cats hate having their food changed, but I trust this doctor implicitly so... I put the new food in Molly's dish and held my breath. Molly gobbled it like this is just what she had been waiting for. Whew.
Update: answers for Barbara
The ear infection was a yeast infection in both ears. Much head shaking, scratching with back foots, and black gunk. Injections of medication twice daily were required, with periodic douches for cleaning which Molly most emphatically did not appreciate. We have no clue how she got it, since she has been strictly an indoor kitty for more than two years.
New food is Innova Evo, and she is still chomping happily on it.