Annatto Seed has a soft earthy quality but is used primarily for coloring while cooking. It's common throughout Mexican, Caribbean and South American cuisines. I first came across Annatto Seed in Peru where it's used to create a golden tone in potato sauces.
In other regions of South America, it's common to see Annatto Seeds used in a paste called Achiote Paste. This paste can be added to meat dishes, fried in oil for color and even added to shakes!