Sadly, Fat Cat died yesterday morning at around 5. He was restless for the first time in weeks and wanted outside. He was a neutered stray who showed up years ago, and loved being outside. I would not let him, of course, because I feared he would go off and hide and die. He settled down, though, and then went to sleep for good.
Fat Cat was a beautiful black tabby, with gold "eyeliner" around his eyes. Not quite the glamour boy as yours, Peaches Lee, but black tabbies are really pretty. I've only seen two in my lifetime. There was also his "attitude"--he could be a real sneaky swiper! Had to always keep an eye on his swiping paw while brushing him, or doing anything else with him.
Ebony Rose, I don't know why I didn't think of sardines. I used to feed them years ago, but the cats at the time stopped eating them and I never thought of buying them again. They are very nutritious and soft.
Thank you all for your suggestions. If anyone still wants to post more, please do, because I am going to remember what is suggested. My oldest cat now is less than 10, but it's still good to have handfeeding recipes for future reference.