One of the things the French left the Vietnamese with, along with a fancy for baguettes, is a fierce coffee habit. No one does coffee quite like the Vietnamese. It's strong, bitter and thick. And with a healthy dose of condensed milk, not for the weak of heart. The fine-ground coffee grains are put into this metal contraption which sits on top of the cup. Hot water is added and the coffee sludge slowly drips into the cup, which is already 1/4 full of condensed milk. You wait about 5 minutes, take off the metal part and stir.