Istanbul Culinary Institute
Enstitu serves breakfast and lunch, monday thru saturday. There is a seasonal menu, a daily menu and a selection of deserts from the house. It's a mixture of international and local cuisine with a special focus on zeytinyagli dishes (w/ vegetable, w/o meat, cooked in olive oil and served cool). It may be tough to find a table in a typical work day, since the place will probably be packed with people from neighbouring companies and tourists.
I remember seeing it when I was in Istanbul a few weeks ago, but didn't check it out. It does look interesting though.
I think it's pretty easy to get to; it's on a street parallel to Istiklal Sk., the long shopping drag off of Taksim Square. Although, we stayed in Cihangir so it was only a 5-10 minute walk from our hotel (without having to hike up any of the crazy hills we discovered over there!)