As Robert Vermeire says in his 1922 Cocktails: How to Mix Them, "The Blackthorn is a very old cocktail, which is made in two different ways." The most...
I did a 2:1 Dolin dry : Cocchi Americano to emulate a blaanc vermouth (however inaccurate), with Powers John's Lane. The lemon twist brings this together in a way I haven't noted since a Sazerac. Light, somewhat fruity (lemon plus fortified wine) and a step on the sweeter side of balanced, but quite enjoyable.