La Parrilla de Thor
This riverfront institution is constantly packed with locals, which is always a good sign that you've come to the right restaurant. The Argentine owner Teodoro Poulsen serves beef and chicken in delicious Argentine parrilla style. Though the restaurant bills itself as the king of steak, you might consider the chicken (milanesa de pollo) instead. To do it right, order a bottle of wine from their excellent wine list to accompany your meal.