Carioca Canuck is right. Go to Porcao in Ipanema but he forgot some very important information. Have a light dinner the night before and very little food the day of the feast otherwise you'll not have room for all the good salads and meat.
I've had great food there the only problem I had was when the waiter said the Malibu was "complimentary" I thought he meant free but he thought it meant it compliments the meal. The drinks wound up costing more than dinner.
Dick