We stumbled upon this restaurant on the way to the Evita Museum. It's a little hole in the wall tucked away on a residential street, and there's no menu. The only questions the waiter asked us were "red or white?" and "how hungry are you?" Then, he started bringing out delicious platters of food.
The atmosphere was very cozy and inviting. We enjoyed the food and the novelty of being sized up by the waiter and given whatever food he decided to bring. We had a great time and will definitely go back next time we're in Buenos Aires.