Pour the cashew milk into a sauce pan and add the agar agar powder. Gently whisk and bring to a boil. Reduce heat and simmer for 2 minutes, then bring back up to a boil. Kill the heat, then add in the salt and black salt and whisk to combine.
Pour the mixture into an egg mold. You can scoop out any air bubbles or scoot them to the middle of the egg since we will be covering that up with the yolk filling.
Let the egg molds chill in the fridge for 15 minutes.
Once set, you can scoop out a little bit in the middle to make more room for the yolk filling if you like.