In a word HUITLACOCHE! It's wonderful, if you haven't tried it, you should. It's hard to find so I was elated when I saw La Major Barbacoa served it. Yum yum yum!
The Green Pozole is just out of this world good. The chichiron on top is a terrific bonus.
I also cannot say enough about the staff. Just absolutely terrific people. Kind, inviting, and attentive. This is my go to spot for authentic Mexico City from now on!