This is an interesting cocktail. I've had either gin or vodka martinis but never both in the same glass until a few months ago. We were at our local restaurant and ordered martinis. A patron next to us started a discussion about James Bond's famous "Shaken--not stirred" comment. So after a little bit of research, we pulled up the Vesper martini, which every James Bond fan will recognize the lines in the recipe below as the first martini James Bond ordered in Casino Royale.
The Vesper according to Ian Fleming and James Bond:"Three measures of Gordon's, one of vodka, half a measure of Kina Lillet. Shake it very well until it's ice-cold, then add a large thin slice of lemon peel. Got it?"
-Casino Royale, Chapter 7
The Kina Lillet Bond speaks about is a White or Blanc Lillet. It's a brand of dry vermouth made in France since the late 1800's that is often referred to as "the apèritif of Bordeaux".
3 measures of Gordon's Gin
1 measure of vodka
1/2 measure Kina Lillet
lemon peel for garnish
Place ice in martini shaker; add all ingredients (except lemon peel). Shake well until shaker is frosty cold. Strain into chilled martini glasses. Garnish with lemon peel. Then enjoy the casino!