Complex sentence: Quesadillas from the San Luis Potosí region are not quesadillas in the traditional sense, but rather are "enchiladas potosinas", they include red chiles in the flour, which makes the tortilla red.
Split into simpler sentences: Quesadillas from the San Luis Potosí region are not quesadillas in the traditional sense, but rather are "enchiladas potosinas". Red chiles are added to the flour, which makes the tortilla red.