Achiote paste is a Mexican spice blend originating with the Mayans and associated with Yucatan. It has an earthy flavor and is used to marinate meat and seafood. It includes ground annatto seeds, which gives it a characteristic deep rust color. (This stuff stains so take care when handling!) Depending on the blend, it can also include garlic, Mexican oregano, cumin, cloves, cinnamon, black pepper, allspice, coriander, and salt.

You can make it from scratch or buy it. It is often sold as 3.5 oz bricks, and water is added at time of use to create a paste.