Annatto seed

The small hard achiote seed, which is also called the annatto seed, is sold both whole and ground. It is prized in Indian and Hispanic cuisine for its slightly bitter, earthy flavor and russet color. In the United States, annatto extract is used to color butter, margarine, and cheese. Here are some other ways achiote seeds are used:

Achiote Paste: specific to Yucatan and Oaxacan cuisine, this paste is made from ground achiote seeds, water or vinegar, and sometimes other herbs and spices such as cinnamon, bay leaf, cilantro, salt, cloves, and oregano. It can be used in moles, tamales, stews, rice dishes, and with meats and seafood.

Achiotina: prominently used in Puerto Rican cuisine, this is a lard compound that has been flavored and colored with achiote seeds. It is used for cooking bean and rice dishes, as well as vegetables, meats, and stews.

Achiote Oil: any bland oil that has been flavored and colored with achiote seeds. It is used in Mexican and Indian cuisine to add a bright reddish-brown color and a distinctive flavor to many foods including fish, fowl, meats, rice dishes, and tamales .

Scent and Flavor: Its scent is slightly peppery with a hint of nutmeg and flavor is slightly sweet and peppery.

Word of Warning: Annatto has been linked with many cases of food-related allergies, and is the only natural food coloring believed to cause as many allergic-type reactions as artificial food coloring.

Source: Wikipedia