In this episode, Gorou-san goes to Ginza to see his friend who is about to open her photo exhibition. She is a Vietnam freak and photos are about Vietnam.
After saying goodbye to her, he walks around Ginza and goes into a Taiwanese tea house. There he orders "Ten-Sai-Hana-Cha (天才花茶)": 天才 means genius and 花茶 means flower tea, and "Taiwan-Sensou (台湾仙草)". I checked Taiwan Sensou on the web and found out it is called "Grass Jelly" in English and this jelly is popular not only in Taiwan but also in Hong Kong, Macau and Southeast Asia. (Wiki). Gorou-san liked the jelly more after he put "Kuro-Mitsu," brown-sugar syrup on it. I think brown-sugar syrup here is similar to dark mollases.