Help with authentic Indian food!
G'raj Mahal for sure! They have a little section on their menu for Goan specialties (I think the chef is from Goa, but I could be wrong). Try the Rechard masala with fish... it's very unusual, super spicy and vinegary. Seriously though, G'raj is some of the best, if not the best Indian food I've had in my life (granted I haven't been to India), and the atmosphere is so, so great.
Southern India near Goa? Do you mean they are Kannadigas from Karnataka state? There is no Kannadiga restuarant in Austin, but Spicy Monsoon is operated by a Bangalorean woman now. Last time I went there, they still had a North Indian-Pakistani menu, as only the Pakistani owners changed but the staff was all the same except they had a Gujarati woman supervising the workers. I suggested she put some South Indian/Bangalorean items on the menu and she said she was thinking she would do a weekend dosa/idli sambar menu---that was a couple of months ago, so I don't know what happened with that.
Aside from that, for Southern flavor there is Madras Pavillion (which I quite like for pure veg. Madrasi food), and Cholas, both of which are Tamil owned. (Tamilian food is of course quite different than Karnatakan, but similar). For me, Madras Pavillian is super authentic and even the buffet is quite decent. I have never been to Cholas.
Sarovar has chefs from Andhra Pradesh (neighbor state of Karnataka) and they do have some Andhra items on the menu, and a mix of North and South items. Aside from the plethora of Punjabi-Mughlai buffet type stuff at a few other places, your only other option would be chaat houses like Bombay Express, Swad, and Curry in a Hurry-all three places are Gujarati owned, not South Indian. Teji's has some very good and very authentic tasting items on their menu, but they are Punjabi owned, not Southern---great goat curry and egg curry.
I don't know anything about South Austin, so I couldn't comment on what is available there.
For South Austin, Indian Kitchen and Whip In are great. When our vendor from Hyderabad is in town, they always go to Indian Kitchen and they say it is authentic. I do like the Bombay Bistro buffet, in Brodie Oaks, quite a bit since 9 of 10 dishes aren't usually found on buffets in Austin. Their menu, which I've never ordered from, does have some Goan dishes.
10710 Research Blvd Ste 126, Austin, TX 78759