I have a mentor with whom I have worked very closely on a significant project since Sophomore year. I was going to ask him to write an “additional” recommendation, but as it turns out, we now have an entire school period dedicated to our project, and my mentor is officially the instructor for the course. Could I ask him for a teacher recommendation instead of an “additional” recommendation now that he is listed as one of my teachers on my transcript?
I believe you can, unless a school specifically requests a teacher in a “core” subject (which your mentor may not be).