Gather all your ingredients: annatto seeds, cumin seeds, coriander seeds, garlic granules, onion granules, dry oregano, ground turmeric, coarse salt, and ground white pepper.
In a dry skillet over medium heat, add the annatto seeds, cumin seeds, and coriander seeds. Toast for about 2-3 minutes, stirring frequently until fragrant.
Allow the toasted spices to cool slightly, then transfer them to your spice grinder or mortar and pestle. Grind until they reach a fine powder consistency.
In a mixing bowl, combine the ground spices with garlic granules, onion granules, dry oregano, ground turmeric, coarse salt, and ground white pepper. Mix thoroughly.
Transfer the sazón mixture into an air-tight container and store in a cool, dark place. It will stay fresh for up to six months.