This is a classic cocktail that I quite often crack out for the request of ‘fruity, a bit sour’. Sure, you sound like a bit of an idiot explaining it’s called a Delicious Sour, not just that it is a delicious sour, but that’s about the only drawback. The original recipe stems from a chap called William Schmidt in 1892, who called for Applejack, rather than the now commonly used Calvados. Applejack is a) quite difficult to get hold of and b) not as nice as decent Calvados, so you needn’t concern yourselves – although if you can get your hands on Somerset cider brandy it makes a great alternative.
There’s some absolutely batshit recipes for this drink just a Google away, ignore them and do this:
40ml Calvados/apple brandy
20ml crème de peche
1 small egg white
Shake the ingredients hard without ice, then again with ice. Double strain into a chilled cocktail glass, no garnish.