Place cherries in a low boy glass and splash with bitters. Muddle cherries until smashed to desired consistency.
Fill a cocktail shaker with ice; pour in rye, vermouth, simple syrup, and lemon juice. Cover shaker, shake vigorously, and pour cocktail over cherries.
I buy a bag of frozen cherries and keep them on hand to use as needed. You can use fresh cherries too.
I have also used honey-infused whiskey in exchange for the whiskey and syrup with excellent results.