In a nutshell: The somewhat retro, thick, rich and creamy egg-based Dutch liqueur.
The lowdown: Advocaat is a liqueur that somehow never quite conquered the world. However back in the 1970s it did actually enjoy a level of popularity for a period. Made with just four ingredients, egg yolks, brandy, sugar and vanilla it's the key component of the Snowball, the 1970s favourite. Just add it to a little lime juice together with ice and lemonade in a long drink glass.