I copied this verbatim from "Zarela Martinez - Food from My Heart (Cuisines of Mexico Remembered and Reimagined)", a cookbook/memoirs that I picked up in a bargain bookstore. I am in the middle of preparing this very recipe and so far it smells heavenly. I hope that y'all will like it too.

Heat the lard or oil in a small or medium size skillet over medium-high heat until almost smoking. Add the achiote and saute', shaking the pan constantly, for 5 minutes. Place the achiote in a heatproof bowl and cover with the orange juice. Let soak overnight in the refrigerator or at least 3 to 4 hours at room temperature. All the liquid should be absorbed and the seeds should be somewhat softened.

Heat a small, heavy skillet or griddle over high heat until a drop of water sizzles on contact. Add the cumin seeds and toast, shaking the pan frequently, until fragrant. Set the toasted seeds aside. Toast the peppercorns in the same manner and set aside. Toast the oregano and set aside. Work carefully while toasting the spices so that they do not scorch; remove them from the pan as soon as their fragrance is released, 1 to 2 minutes. In the same skillet, roast the garlic cloves over high heat, turning several times, until dark on all sides and somewhat softened, 5 to 10 minutes. Peel the garlic and set aside with the spices.

Place the soaked achiote, salt and spices in a blender or food processor fitted with the steel blade. Grind thoroughly with a pulse motion, adding more water or orange juice, if necessary. Work in batches, if necessary. The mixture should be a smooth paste. Refrigerate until ready to use.

Can be stored, tightly covered, in the refrigerator several weeks, or indefinitely in small containers in the freezer.