You are making me hungry for acaraje, so I'll have some for lunch. If you want the food without the incredible colorful experience of the Feira Nordestino, you can find this food in Copacabana at Siri Mole, which has been in the same place as long as I can remember. I went there on one of my first dates with Mrs jbc, 35 years ago or so. The prices are by Rio standards modest, the food is superb, and they have acaraje! Not only that but they also have Devassa Ruiva, one of my favorite beers.
http://www.sirimole.com.br