One place that my family has been picking up prepared from recently is this Keralan grocery store along Milwaukee Avenue in Glenview.
There's a few snacky items in a warming tray by the front register - both meat and vegetable samosas as well as fish cutlets, but the real bounty is in the back refrigerated section which has containers of numerous Keralan dishes for takeout. They also have some non keralan, more generic Indian dishes such as chili chicken available
I think the "wet" dishes in particular are pretty good - I enjoyed quite a good duck curry recently, the "fry's" are also pretty good but I think Malabar Catering's are a little bit tastier
The meat samosas and fish cutlets have a nice spice punch too.
On the grocery front - there are quite a few interesting pickles that you don't see in other indian grocery stores and some homemade pickles, including fish pickle
Kairali Indian Foods
777 Milwaukee Ave
Glenview, IL 60025