The flavours of cassia and cinnamon are subtly different – both contain a volatile oil giving the warm, sweet flavour we associate with cinnamon but cassia (from Vietnam or Indonesia) contains more of this oil so is hotter and stronger. Cinnamon is incredibly versatile and lends itself well to both sweet and savoury dishes. True Sri Lankan cinnamon - despite containing less of this oil - also contains eugenol which gives different flavour notes of clove and citrus.