Add all of the ingredients to the spice/coffee grinder
Mill into a ground consistency
Store in an airtight container for several months and use accordingly
Notes
You can purchase annatto from a Latino supermarket or buy it online.
Don't forget to utilise the substitutes if you cannot obtain annatto (saffron thread, paprika, turmeric)
The use of both onion powder and pink salt is optional. Some people like to omit the use of salt and add it on an individual basis. I personally prefer to include all the listed ingredients during the preparation stage.
Mix your sazon together either by hand, mortar and pestle or using a spice/coffee grinder.
Store your homemade spice in a glass jar
To avoid volatility do not store in direct sunlight
The spice mix should last up to a year. Don't forget to label it!