Doña Teo is the quesadillas lady. She's serious and reserved, never speaks more than what's strictly necessary. My kind of gal. She has her stand in Santa Maria Tonantzintla, a small town famous for its church, one of the most elaborated ones I have ever seen. Build by local artisans, portrays angels and cherubs with indigenous features, showing the syncretism present in every aspect of mexican culture.
Quesadillas are more than just melted cheese inside a tortilla. They can have all sorts of fillings such as mushroom, squash blossoms, corn smut, pork rind and longaniza (a mexican, spicy sausage)
Teo makes everything from scratch. Her quesadillas are the best. Handmade tortillas, Oaxaca cheese, epazote and the filling of your choice. My favorite combination is pork rind and mushrooms. Superb!
You can also try the gorditas, a tortilla filled with fried black beans and covered with salsa and cheese. You can choose between green salsa or red salsa or ask for a 'bandera' which has both of them.