Basically a perfect Manhattan with equal proportions less the bitters, the Whisper is a good cocktail when fresh vermouth is used.
The perfect Manhattan is a variation on the good old Manhattan, a variation which calls for equal proportions of sweet and dry vermouth. The change here makes for a rather more complicated cocktail, pulling out different flavors on account of the inclusion of another ingredient, that being the dry vermouth. Since you can use a different brand of dry vermouth than sweet vermouth, the drink is easily quite variable, and much more combinations of flavor can be unlocked when mixing the libation.
A whisper, as a drink, is reminiscent of the actual function of a whisper, coming out a bit more quietly than with the bang and style of a Manhattan. A favorite in the West Indies according to Harry Craddock (174), the reason is because the Whisper as a cocktail lacks bitters, something which helps to bring out the full potential of the drink. Bitters are an essential ingredient in classic cocktails, but are not something that a lot of people, whose palates are accustomed to sweet and cloying, are familiar with anymore except in tea or coffee. As such it adds another layer of flavor, another dimension, with notes of various herbs and spices to bring out further complexity in a drink, while not completely changing the tone of the cocktail.
When mixing a Whisper, you can get around the lack of bitter component by using a bitter vermouth like Punt e Mes. When juxtaposed with something like Cinzano dry vermouth, and the high herbal characteristics, you get an overall nice experience; or if you wanted to go for something a bit more refined, the utilization of Carpano Antica works wonders at providing an extremely pleasing experience with the overall drink. The equal proportions called for in this drink helps make the vermouth the entire focal point, so changing it out really changes the overall drink, and to maximize the pleasure of imbibing it, one should ensure the utilization of fresh vermouth (as is always the case with the fortified wine).
Anyhow, if you want to make sure the whiskey does not get lost in the drink, try a stronger and more assertive whiskey such as a rye whiskey, rather than a bourbon, or better yet a very rye driven bourbon; Harry Craddock’s book, one of the first places the cocktail appears, does not specify, and only provides an equal proportion ratio (ibid). However, you can easily make this into something that is a bit more spirit forward by increasing the spirit’s ratio to that of the vermouth; yet personally, the cocktail is one that should be more driven by vermouth, since the original recipe actually calls for that, and we wouldn’t want another thing that is a less complete Perfect Manhattan, so keeping to the original ratio might be wise in this case.
3/4 ounce whiskey
3/4 ounce sweet vemouth
3/4 ounce dry vermouth
Stir the ingredients together in a glass with cracked ice until well chilled, and strain into a chilled cocktail glass.
Craddock, Henry. 1999. The Savoy Cocktail Book. Originally published 1930. London: Pavilion Books.