This is the Ramazan Efendi Mosque, the last mosque built by Sinan. It's from 1586. It has famous faience from the best period of Iznik production. The imam - whom I asked if I could take some pictures after prayer ended - didn't give me a chance to take pictures, my impression was that he wanted to hurry off to lunch, I hope it tasted well, I left with a foul taste in my mind.
You can see more of the region where this and several others is situated on my Istanbul Seventh Hill gallery.