"Evil twin" was bartender Janet South's nickname for Godiva white-chocolate liqueur, the lesser-known sibling of Godiva dark chocolate liqueur...
Ice
1/2 ounce vodka
1/2 ounce white-chocolate liqueur
1/2 ounce dark-chocolate liqueur
1/2 ounce Chambord
1 raspberry
Fill a cocktail shaker with ice. Add all of the ingredients except the raspberry and shake well. Strain into a chilled martini glass and garnish with the raspberry.