Heat milk over medium high heat with slices of ginger. Bring to a boil. Watch the milk closely as it takes about 1 second for the milk to boil over and make a mess.
While milk is heating combine all the other ingredients in a bowl.
Whisk together until well mixed.
Once the milk starts to boil, remove from heat and pour into the egg yolks mixture. Quickly mix to combine.
Add back to sauce pan over medium low. Simmer for about 10 minutes or until the custard starts to thicken.
You're looking for about this consistency... if this picture helps at all.
Add chia seeds and mix into custard
Allow to stand for about 10 minutes. Stir, and then leave for another ten minutes. Refrigerate until cold. This will hold in the fridge for about 4 days. Water may fall out of solution, if you let it sit. A quick stir will recombinant it all.
