I could not find more than a notice on this (heavily restored) mosque, which has a medrese nearby:

Orucbey Kızı Sittihatun Camii 1459-1460.

The mosque is part of a small complex that was built in 1460, commissioned by Sitti Hatun, a daughter of Oruç Bey, the second son of Kara Timurtaş Paşa. The latter was grandson of Aygut Alp (a famous comrade of Osman Gazi, the namesake of the Ottoman dynasty) and was appointed ‘beylerbeyi’ (governor) by Murat I. His son Oruç Bey was the first known court historian of the Ottomans; his daughter Sitti Hatun became the first wife of Zağanos Mehmed Paşa, a life-long companion of Fatih Sultan Mehmet II, with an impressive career as tutor, army commander, Grand Vizier and Governor. No wonder his wife had some money to spend on community service.
The Sitti Hatun Mosque is also called ‘Kanberler Camii’ (Mosque of the Kamberler neighbourhood).

On the picture: The marble ‘kitabe’ (building inscription), which mentions ‘Sitti Hatun, daughter of Oruç Bey’ as the commissioner. It is 1,52 m wide and 40 cm high, and is placed above the entrance of the prayer hall. The language used is Arabic, written in elegant sülüs script.

Sülüs (from Arabic: ثلث‎ ṯuluṯ "one-third"), also referred to as ‘thuluth’, is a script variety of Islamic calligraphy invented in Persia, which made its first appearance in the 11th century AD. The straight angular forms of the older Kufic script were replaced in the new script by curved and oblique lines. In Sülüs, one-third of each letter slopes, from which the name (meaning "a third" in Arabic) comes. It is a large and elegant, cursive script, used in medieval times on mosque decorations and inscriptions.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Vakıf Abideler ve eski Eserler (volume III)’ - Vakıflar Genel Müdürlüğü, Ankara 1983 & Wikipedia.