Condensed milk — properly sweetened condensed milk — is cow's milk that has had about 60% of its water evaporated away and a large dose of sugar stirred in, leaving a thick, glossy, pale-gold syrup that is intensely sweet and richly creamy. Shelf-stable for years in its sealed can, it needs no refrigeration until opened, and it is the foundational sweetener-and-dairy in one behind desserts around the world, from tres leches and key lime pie to Vietnamese iced coffee and Brazilian brigadeiros.