Add the 3 ingredients for the egg white to a blender, and blend at maximum power for about a minute. Depending on the blender used, it may be necessary to clean the inside of the blender with a spatula a couple of times during the process.
Place silicone mould(s) on a flat baking tray, ready to be easily moved.
Transfer the silken tofu mixture to a pan and start heating on medium-low, stirring constantly until it reaches the temperature of around 90°C (195°F), that means just before it starts to boil (it's not essential checking it with a thermometer). As soon as the mix begins to form the first bubbles, you will notice that it will tend to thicken almost instantly.
It is the time to transfer the mixture as quickly as possible into the silicone moulds. Fill the cavities generously and, again with a spatula, remove the excess from each cavity while trying to press the mixture as much as possible to prevent air bubbles from forming.
Allow to cool at room temperature for 30 minutes, then you can transfer everything to the refrigerator.
Meanwhile prepare the egg yolk sauce according to this recipe.
Stir into the sauce the dehydrated potato flakes, and let this mixture cool down too.
Once the egg whites are firm enough, remove them out of the silicone moulds.
With a sharp knife, remove any excess until the two halves match perfectly to a perfect egg shape (use the off cuts for sandwiches or salads).
Now, using a watermelon baller, remove a half sphere from the base of each egg half, right where the yolk would be.
Fill the hole with the yolk mixture, and there you have your vegan hard-boiled eggs ready to be enjoyed or featured in our favourite recipes.
For best results no ingredients should be left out or substituted.