What good is a Matunga guide without any mention of South Indian food? The last word on the street is that you should go to Rama Ashray. Our recommendation is the butter idli and the Mysore dosa, both of which are phenomenal.
P.S. You’ve also got to have the filter coffee at Arya Bhavan and the uttapam at Sharda Bhavan, both of which are on the same street.