Soak the tapioca in water for 2 hours to soften them up
Put water into the bottom pan of the double boiler
Heat it up to boiling
Put the top pan on the double boiler and add milk to it.
Stir in the pearls
Cook them until they are clear, stirring periodically (about 50 minutes, possibly more)
In another bowl, whisk the eggs, sugar, salt, and flavoring. Make sure to get a good blend here.
Stir in a bit of the heated milk (this tempers the egg)
Slowly add the egg mixture to the tapioca
Now start stirring again.