This is a simple cocktail - but like everything about cocktails... there are variations, and multiple people who claim inventing it. We've gone with the simplest version; but we've seen it made with a dash or two of bitters, Vodka instead of Gin. There is even a completely different cocktail also called the Montauk that is a riff on Long Island Iced Tea. Oh well.
Ingredients:
1 oz Gin
1 oz Dry vermouth
1 oz Sweet vermouth
Garnish: Lemon twist
Glass: Rocks
Method:
Fill a rocks glass with ice.
Build all the ingredients into the glass. Stir to combine and add more ice if needed. Rim the glass with a lemon twist and drop it in to garnish.