Put a tumbler in the fridge to chill until cold. Meanwhile, pour the whiskey, vermouth and bitters into a mixing glass or jug along with a handful of ice cubes. Stir until the outside of the glass or jug feels very cold. Fill the chilled tumbler with ice, then strain in the cocktail.

Twist the strip of orange peel over the drink to express the oils, then discard. Garnish with a cocktail cherry to serve.