This was something I just whipped up for tonight's drink special.
1 1/4 oz Leopold brothers tart cherry, or cherry herring
1/2 oz creme de cacao dark
3/4 oz lemon juice
3/4 oz simple syrup
2 dashes lime bitters
1 bar spoon bourbon
1 egg white
Combine all but bourbon and dry shake hard for 10-15 seconds. Add ice, shake again to chill. Strain into a sour glass or some other kind of stemware filled with ice. Float the bourbon in top. Garnish with a cherry.