Ahhhh, pisco sours! I first sampled this fantastic cocktail when visiting Chile in 2008 on a Habitat for Humanity house build project. On my return to Chile in 2010 I was keen to have another authentic one as those I had tried in the UK just did not match up.
Pisco sours is made from pisco, lemon or lime juice, egg whites, syrup and bitters. Interestingly both Chile and Peru claim it as their national drink and so there remains debate over its origins. To be honest, I don't really mind where it has come from, I'm just happy it exists! A trip to either Peru or Chile should definitely include a sample of the drink! (be warned though it is very strong!)