Mix the whiskey, Angostura bitter and the sugar syrup in a glass with ice cubes. Pour into a cocktail glass (without the ice cubes).
Now cut a small piece out of the lemon peel. Squeeze the piece of peel over the drink so that the essential oils of the lemon are splashed onto the drink.
A cocktail cherry can be added to the glass. Otherwise do not use any other garnish for the whiskey cocktail.