strictly a vesper today is not what monsieur james bond would have had at the time when the books were written … simply because the recipe of one of the ingredients has changed over the years (as probably tastes have changed too)!
basically, a vesper is like a good martini … only more potent. most recipes tell you to mix 6 parts gin, 5 parts vodka and one part lillet blanc plus a bit of lemon zest, shaken with ice and strained (always shaken, not stirred!). personally i prefer a mix with a bit more of lillet blanc and a dash of orange bitters (i.e. 6 parts gin, 5 parts vodka, 3 parts lillet blanc), but that is a personal preference. i just find that the slightly heady aroma of the lillet really adds to the cocktail if used more enthusiastically 🙂
i said that a vesper nowadays is not what mr bond would have had, due to the fact that the recipe of lillet has changed. the original lillet was supposed to be much less flowry and fragrant in taste with a bigger part of bitterness than the one we can get nowadays. but nonetheless, a vesper is grand! a slight warning though – one is more than enough, as otherwise one might end in a delirium quickly. do i need to add that a good quality gin and good quality vodka go a long way to uplift a simple drink (i used danzka vodka and bombay sapphire gin) 🙂