Annatto seeds, also known as achiote, are small red seeds (they also come in a paste), similar in size and shape to fenugreek seeds. They have been used as dyes in South America since pre-Colombian times, and continue to lend their burnished orangey/red color and subtle flavor to dishes found in tropical areas. They stand out in Mexico's Yucatecan dish of Cochinito Pibil, where they are ground and combined with spices to create a vibrant spice rub for pork before it is slowly cooked in a banana leaf. Whole annatto seeds are often steeped in hot fat, which is then used to start a dish. Annatto infused oil can make a lovely red rice reminiscent of the Caribbean. Buy these seeds or their paste in Latin food markets and spice shops, or pick some up next time you are in Mexico!