learning theories like Classical conditioning, Operant conditioning, Social learning, Gestalt etc. could explain how learning takes place, but what about how teaching takes place?
Well teaching has always been an active and conscious process so the term 'teaching theory' may not be that popular (although there are many teaching methods/techniques) but learning theories actually facilitate understanding the teaching learning process. How students learn ultimately leads to how teachers should teach, so both go hand in hand. We are past the born teacher myth age and in this e learning era teachers have to be on a constant check which methods to use for teaching, reconceptualize teaching from teacher lecture to collaborative construction of knowledge and utilizing and adapting all theories to the best possible use.
Tracing cognitive pathways of teachers would be an interesting research. Whereas meta learning is a popular term, I guess it is taken for granted that a teacher is already aware of and in control of the teaching process, that's why teacher training is emphasized much.
Teaching is much more difficult than learning; people are constantly learning, in every situation, whereas teaching is a very special situation, with a high risk of failure.