Chawanmushi (茶碗蒸し) is a Japanese hot appetizer.  It is a type of egg custard, but not sweet. You might find it at sushi restaurants or a little more formal Japanese restaurants in Japan.  “Chawan” means tea cup or rice bowl and “mushi” means steamed in Japanese, and it is indeed steamed food in a cup.   Chawanmushi’s flavor comes mainly from Dashi, soy sauce and mirin, and even though Chawanmushi is a savory dish, the texture is similar to egg flan.