ascherer I'm a a fan of the Fee Bros. Aztec Chocolate bitters, too. You may have noticed I've got bottle tucked in the back in the photo above. Good compliment to a Grand Manhattan.
I like to make a variation on the white Russian with the chocolate bitters. Instead of plain cream/milk, I slowly simmer some cream/milk with cinnamon sticks and chili pepper beforehand to infuse some extra flavor. Strain and chill the milk in the refrigerator before use. Then, when cocktail hour comes, I mix the Kahlua, vodka, and flavored cream (often I use 1/2 & 1/2 or milk if that's all I have), and Fee Bros. Aztec Chocolate Bitters over ice. I don't have a name for it...maybe I should call it the Trotsky?