Name that book: child detective, cookies

I’m wondering about the name of a children’s book. The main character was a young girl who solved crimes but she needed to eat cookies. The tag line was “...and she ate another cookie”.

Thanks!

Hi and welcome to Librarything! You'll probably find the answer you seek in our Name That Book! group, where they specialize in finding lost titles:
https://www.librarything.com/groups/namethatbook

Please be sure to read the group's header for instructions on posting your request, and click the Post New Topic directly below this header.