The filling of these buns is made of salted egg yolks, butter, sugar, milk and custard. When the buns are steamed, the filling melts and flows out like molten lava, hence the name “molten lava buns. The filling is slightly sweet, creamy, and has a slightly salty and muddy texture due to the mashed salted egg yolks 1. The buns are also known as 黃金流沙包 in Chinese,