My favorite is Nielsen-Massey Madagascar Bourbon Vanilla Extract, which can be found at specialty food stores and many kitchenware shops. Extract actually improves with age like a fine wine and keeps indefinitely. To make your own, steep the bean in a small glass container of vodka or brandy. Made by soaking beans in alcohol and water for several months, the brown liquid is richly fragrant, unlike imitation vanilla, which is completely artificial and often bitter. It's sweet, floral, elegant, soothing to the tongue and pleasing to the palate.
Coffee compliments the flavor of chocolate.
Instant espresso powder can be found in Italian delicatessens and many supermarkets. If you wish, you can substitute regular instant coffee, but it isn't nearly as intensely flavored. It is important that the ground cinnamon you use is fresh. Cinnamon loses strength when opened, tightly seal the unused portion. Vinegars are made from a variety of ingredients, including wine, beer, hard cider, and grain alcohol, and each type has its own characteristic flavor.