Ceylon cinnamon and Cassia cinnamon differ primarily in flavor and appearance. Ceylon cinnamon has a milder, sweeter taste, while Cassia cinnamon has a stronger, spicier taste and a darker color. Ceylon cinnamon has thin, fragile quills with a paler light tan color, whereas Cassia cinnamon sticks are thicker and reddish-brown. Ceylon cinnamon is often considered the "true" or "sweet" cinnamon, while Cassia cinnamon is more commonly found in many supermarkets. In our experience, they can be used interchangeably in most recipes.