Chef Ranjana has been offereing authentic vegeterian cooking classes in her home for many years. She is widely known in the community. You can read all about her on her website: http://www.indiancookingclass.com/introduction.html
You can read reviews of her classes here: http://www.yelp.com/biz/ranjanas-indian-cooking-classes-chicago
I am registered for two of her classes (South Indian on 11/10 and North Indian on 11/24). Classes are $75 individually, but cheaper if you buy more. You make 9 different dishes in the class, then sit down to a meal of the foods that were made. Classes seat 8 people. The class runs from 9;15 to 12:15.
Visit her website above to register. You will need to email Ranjana or call her, and pay, to secure a spot in the class.