Basics:
- iPad Pro connected to a MacBook Pro
- GoodNotes for the writing app in the iPad
- Sennheiser wireless mic for audio
- A corded webcam (logitech)
- Telestream's excellent ScreenFlow for recording everything and then editing
- I also made a template for all of these videos in ScreenFlow to make things easier (I can share this)

I recorded some of the workflow here:
https://www.youtube.com/edit?o=U&video_id=946S21yIhyU

And more here on how I record in-class lectures:
http://www.uvm.edu/pdodds/teaching/courses/2015-08UVM-300/things/video/