Ageus T.
Yelp
It's the best coffee I had in Istanbul, incredibly flavorful, you can in fact taste the floral tones. The interior design and atmosphere is incredible, extremely modern yet has the odd telescope or oldtimer to add a bit of flair. Like some other coffee joins, it gives you a card so for buying 10 coffees you get one for free. The only drawback is the location. It's not very easy to get to and the there isn't much of a view.
The desserts, while seemingly healthy, you know no glutons, no sugar, no fat, basically anything that makes a dessert tasty, resulted in one of the most dense brownies I've ever tried to eat. So as long as you stay away from the desserts, you should be fine.