The village of Varāy (Viyar) is located at the foot of Āq Dāgh Mountain in the southeast of Sultaniyya, Iran, and is known for its impressive rock-cut architecture called Dash Kasan. The history of Sultaniyya, which later became the Ilkhanid (Mongol rulers) capital, began with the issue of an order by Arghūn Khan (1258–1291 CE), to build a huge city enclosed by stone walls and fortifications. According to many in the field, Dash Kasan occupied a prominent place in the development of Arghūn’s architectural project; first as a stone quarry, and then as a Buddhist monastery. This building is unique in its architectural design and decoration. The site’s two large-scale dragon snakes carved out of cliffs, and the development of a vast open space by cutting the solid rock are the only examples of their kind in Iranian art and architecture. Although most of the debates on the identity of this site to date are centered on its religious function during the Mongol period, there is little architectural evidence to support this idea. Hence, the nature and the scope of earlier studies are not sufficient to substantiate the architectural discourse surrounding this monument. The aim of this paper is to study this enigmatic rock-cut complex to provide a more detailed description of the current remains. According to the results, the architectural layout of this building suggests it was originally designed as pre-Ilkhanid Mongolian ceremonial halls and reflects a Chinese, East Asian architectural influence that was evident and pervasive throughout the Mongol territories.