My husband and I recently spent 6 days in BA. We had a wonderful experience eating our way through the city! We stayed at the very cool Bobo hotel..which despite the bizarre name (shortened for "bourgeois bohemian") had amazing service and adorable rooms. Just don't expect much from the food> They brought out dishes that looked beautiful, but the taste was very lacking. It's a cozy place for a cocktail, though!
A couple of our best lunch meals were had at two vegetarian spots -- Bio and Krishna. Bio had quinoa on the menu -- a sign for us that they knew what they were doing. We had delicious empanada to start and a wonderful fresh salad. Our main courses were hearty and healthy -- filled with mushrooms and eggplant. They brought us a homemade ginger/lemonade drink to start. Great touch.
Krishna is less gourmet but the atmosphere is very funky and you sit crunched up and knocking knees in a square room facing other patrons. The food is basic and yummy -- steamed veggies with rice and a nice little dressing. We needed that after other heavy meals and many dulche de leche cookies and treats each day. They offered us a shot of chai tea at the end of our meal.
Our requisite steak dinner at La Cabrera was incredibly memorable. We don't normally eat red meat, but when in rome we decided...La Cabrera is the kind of place that serves a main dish big enough for two (three even.) They also bring sides with the main dish, so you needn't order any. (We didn't realize this) The sides came in tiny little bowls, almost like small ramekins, filled with olives, mash potatoes and others.
We had a lovely dinner at Bar Uriarte...although we had travelled that day so we were a bit too weary to really pay attention to the veal ravioli (my husband) and salted chicken dish (me). Still, with a few more hours of sleep it might have tasted more memorable.
Cluny -- eh. It didn't really wow us with anything.
We wanted to try Olsen but didn't get a chance to...we were in BA during the flag day holiday and it turned out many restaurants were closed.
We had amazing ice cream -- probably our best ever -- at a very chic place a couple doors down from the Alteneo book store (a former opera house worth strolling into.) Layer a dulche de leche flavor over anything and you'll be in heaven.
I thought I'd write these recommendations down because I used this site to comb through the postings before our trip. I hope it helps!