Basically a simplified Martinez, this cocktail appears in Jacques Straub's 1914 book, "Drinks" with the following instructions:
Turf Cocktail No.2
2 dashes Angostura bitters
1/3 jigger Italian Vermouth
2/3 jigger Holland Gin. Stir
Super simple, I used 2 oz of Zuidam 5 Oude Genever, 1 oz of Carpano Antica Italian sweet vermouth and added a lemon twist.
Not quite dark, not quite light...if there was a "medium and stirred" category this would qualify. It's nice, I also noticed the flavors improving as the drink warmed a bit.