Annatto is a natural food coloring and mild seasoning made from the reddish-orange seeds of the achiote tree (Bixa orellana), a shrub native to tropical Central and South America. Also known as achiote, it has been used since long before European contact to tint dishes a deep yellow-orange and add an earthy, faintly peppery flavor.
It is a staple in Latin American, Caribbean, and Filipino cooking, where it colors and flavors rice dishes, stews, marinades, and sauces, and is also used to tint some cheeses (such as Red Leicester) and butter. The seeds are usually infused in oil, water, or fat rather than eaten whole, since their color is far more pronounced than their flavor. Annatto pairs well with garlic, onion, tomato, chili, cumin, oregano, and cilantro.
It should not be confused with saffron or turmeric: all three color food yellow to orange, but annatto has the mildest flavor and is the least expensive of the three.