The Old Portland Cocktail

Ingredients
  • 1 1⁄3 oz Bourbon, Old Weller Antique 107
  • 1⁄2 oz Dry vermouth, Dolin
  • 1 t Blackberry liqueur, Clear Creek
  • 2 ds Bitters, Angostura
  • 1 twst Lemon peel (expressed and inserted)
  • 1   Blackberry (skewered, as garnish)