Is there a book like ‘Phoenix from the Ground Up’? Basically, it would be a book that instead of focusing on using Phoenix, walks the user step by step through creating a mini-Phoenix.
Not sure this is what you’re looking for, but the Elixir & OTP course from Pragmatic Studio walks you through creating a minimalistic web application from scratch (not even using Plug).
There is also this serie… from @shankardevy
The Garuda book is about rebuilding Phoenix from the ground up.
BUT… it’s for Phoenix 1.3 and a lot have changed since.