Sữa Hột Gà
Also known as egg soda milk or bird’s nest drink, this is a popular Vietnamese beverage, and it is exactly what it sounds like.
Take one egg yolk, usually from a quail egg (although chicken eggs may be more common in America). Add about two tablespoons of condensed milk. Top off the glass with club soda, and stir until fully combined. Serve iced.
The origins of this drink are unclear, but it is easy to see that carbonated custard is a good thing, and was bound to be invented eventually.