Essentially, in a Manhattan, you’re taking the structure of the Old Fashioned from a spirit/sugar/bitter standpoint, but adding a bit more complexity with the sweet vermouth’s flavour and aromatic profile.
Simply put, there’s a reason the Manhattan has changed little since its creation, and why so many cocktails are modelled on its 2:1 spirit-to-vermouth ratio. It’s been proven time and time again to be an ideal structural balance of each component.
Shake and strain over ice…
Garnish with a lemon twist or Brandied Cherry
Enjoy!