Ask her to cook for herself so that she can make exactly what she wants.

Ask her -exactly- what she wants to eat. For three days. Have her write it down. Keep the list as proof. Fix just that (for her anyway). Do not accept her saying, "oh, anything is fine ..."

If she still complains after you've given her exactly what she's asked for, never fix her anything again!

Treat her like a picky toddler. Have a well balanced meal and make sure there's one component at each meal that you know she likes. If she complains, tell her "Mom, we do this thing now where we don't complain about the food I make and serve."

Ask her what she wants and order it for her. Don’t lose your mind trying to cater to her.

I would be triggered too. My mom would sneer at 99% of restaurant food and criticize to no end, and she didn't care for my cooking, so mealtime with her was always fun.

How about stocking food items that you know she'll eat, and then proceed to feed your family normally. If she doesn't like your family meal, she can help herself to things that she normally would eat. Then plan on getting take outs for 2 dinners, maybe.

I have the opposite problem.

My mother can be extremely irritating in other areas of her life, but her food pickiness is actually very healthy: she likes steamed vegetables, eats very few carbs, no rich sauces, just a little bit of lean protein, a bit of fruit.

So when she visits, I make the effort to cook what she likes, even though my family hates it, because it's good for everyone!

She's very picky. There are a lot of foods and food preparations that she won't eat. I should just ignore it and feed my family but it triggers me. I don't want to spend dinner in a state of annoyance.

Just order out for three days? That doesn't sound good either.