Toast the coriander seeds in the saucepan where you will make the porridge. Toast them on medium-high for about 3 minutes or until they become fragrant. Transfer the toasted seeds to a mortar and pestle and smash them into a powder.
Add the fonio, almonds, coconut oil, and 1/2 teaspoon of the coriander powder to the saucepan and toast everything on medium heat for about 5 minutes, stirring often.
Add all the milk, vanilla, and salt, bring to a boil, then lower the heat to low and simmer until you get a porridge consistency (about 5 minutes). When it's creamy, turn the heat off, cover it with a lid and let it rest for 5 minutes.
Warm the blueberries if you are using frozen. If you are using fresh, just mix them into the porridge when serving. Season with more coriander powder, drizzle with yacon syrup or honey to your desired sweetness and serve warm. It can also be served cold.