Farmer’s wife shrinks suddenly, unexpectedly, and often. At a store, she shrinks and falls into an open bin of dry macaroni. The farmer hears only “macaroni, macaroni!” as her tiny voice cries out. Another instance has her riding on the back of a crow. This could possibly be a stand-alone book, or it could be a story in a storybook collection.
It’s Mrs. Pepperpot and the Macaroni, a.k.a. Mr. Pepperpot Buys Macaroni, but I think the book you want is the collected stories, Little Old Mrs. Pepperpot.
To start, we’re definitely talking about ‘Mrs. Pepperpot Buys Macaroni ‘ by Alf Prøysen. He wrote a whole bunch of Mrs. Pepperpot stories that I get the sense were published and republished in various combinations lots of times, and I’m not familiar with the one with the crow, but this should help narrow things down a bit.
Mrs Pepperpot series.
https://en.wikipedia.org/wiki/Mrs._Pepperpot#:~:text=Some%20of%20the%20Mrs%20Pepperpot%20stories%20are%3A%201,Mice%20and%20the%20Christmas%20Tree%20More%20items…%20
One of the stories is actually called Mrs Pepperpot Buys Macaroni.
Mrs. Pepperpot!
Mrs. Pepperpot by Alfred Prøysen maybe.
This sounds like the Mrs Pepperpot series by Alf Prøysen. One of the books is Mrs Pepperpot Buys Macaroni.