We had a nice trip to Istanbul this May and here are some of my thoughts on various food establishments.
Imbat - Very good, modern take on traditional Turkish cooking. The view of the city, Galata and the Bosphorus from this rooftop hotel is very nice. Went to the earlier seating so we can enjoy the change from day to night. Great, attentive service. Price-to-value ratio excellent!
Cukur Meyhane - Not really a secret judging by the mixture of locals and tourists. Simple old school place just off Istiklal on a side street in a half basement. Very good and diverse mix of mezes (small plates). We really enjoyed the seafood meze. It's a good, inexpensive place to spend an evening drinking beer, wine or raki. Two words....fish ravioli.......with yoghurt sauce......Ok, five words.
Furreyya - Small, charming restaurant in the bustling Galata Tower area. Simple menu, but very good fish dishes. Whole grilled fish is probably the best way to go. Seafood in Turkey seems expensively priced in US$. This was very straightforward and reasonable. No hidden charges, no incoherent weighing of the fish on a scale. We decided to avoid the hustle at Nevizade's fish restaurants and have drinks there later for the ambiance. (As a note, we had fresh seafood twice later in the trip on the Turkish West Coast.) Furreyya has wine and beer.
Ciya Sofrasi - I am torn on this one because the hype over this place is over the top. There are literally guidebooks in the hands of many clientele. The place is famous for preparing old Turkish meze recipes for salads, vegetables and beans. It's relatively inexpensive if you stick to vegetarian fare. Oddly, the bread and soups are very average. The confusing part is there are three locations across from each other. One has everything, but no alcohol. Another has meat kebaps, but no alcohol. The one we ate at had more vegetarian fare with little meat, but served beer and wine. We felt like we needed kebaps with the veggie meze and they will bring the kebaps from the other restaurant across the pedestrian street. I would say that the Asian side's Kadikoy and Moda neighborhoods are very nice areas to check out. They are away from Istanbul's hardcore tourist zones on the European side. However, I wouldn't make this trip for Ciya Sofrasi.
Burc Ocakbasi - Located in the Grand Bazaar it's very good charcoal grilled turkish food. It's a very tasty and cheap lunch in a side alley of the bazaar
Siirt Seref Buryan - Delicious, casual and outdoor dining under the ancient aqueduct. Tender lamb cooked in an underground pit served on a turkish bread (like a thick pita). The encrusted chicken pilaf was okay, but not really the reason to go. Anthony Bourdain went to the competitor down the street, but further from the aqueduct, Sur Ocakbasi. We took bus #87 after Chora Church and got off at Itfaiye Park with the help of some nice local ladies. It's on the other side of the park past the aqueduct. Juice, soda and aryan (yoghurt drink) are served.
I call this next section Snacks Around Beyoglu. We stayed in the Cihangir neighborhood of Beyoglu.
Kizilkayalar - Tried the famous wetburger on the now infamous Taksim Square. (The protests might have been in their infancy, but we did not notice.) The wetburger is a nice, guilty pleasure, but not worth a special trip if you are not near one.
Durumzade - Charcoal grilled durum wrap. We shared a fantastically spiced double adana durum (10 TL). This would be a good lunch for most. Ladies might prefer the regular. If you are hungry after visiting the bars near Nevizade, I believe this place is open late.
Karakoy Gulluoglu - Many people say this is the best baklava they have ever had. Some dispute this. Trust me, this is the best. It's right near the Karakoy ferry and tram stop. On weekends, it looks like several generations of Istanbulites share this experience together.
Ismail Kebapcisi - This was recommended by Istanbul Eats as the best lahmacun (minced lamb served on a thin, oven baked dough). Some call it Turkish pizza. I think I prefer durum over lahmacun. This is now across from the German Hospital in Cihangir. In fairness, they make other items in their wood oven including pide.
Haci Bekir - We love the original Turkish Delight. Several locations, with the original traditional store near the Eminonu and Sirkeci tram stops.