book about a disabled witch who bakes magical cookies?

My friend is looking for a book she can't remember the name of. They described it as a book about a disabled witch (possibly CFS) who bakes magical gingersnaps.

They think it was published pre-2020.

additional info:

• I'm positive it was an adult book, not YA
• I'm positive it was contemporary fantasy bc the witch kept her gingersnaps in a Tupperware container
• I don't think it was a mystery, but I'm less sure of that