Fill a cocktail shaker or pint glass two-thirds of the way with ice. Add gin or vodka and vermouth and stir with a cocktail spoon until chilled, about 30 seconds. Strain into a chilled cocktail glass and garnish with an onion or two.
The cocktail was created in the early 1920s in Detroit, where it was first served at the Detroit Athletic Club. Later Frank Fogarty introduced it to New York and in 1951 its recipe got published in Ted Saucier'sclassic cocktail book Bottoms Up!