Soak the pearls in water overnight, covered well with water. Drain the water off.
Heat the milk, cream, vanilla bean (split and scraped), and tapioca to a slow simmer in a heavy pot and cook for 1 hour, stirring often.
Add the sugar and salt. Bring to a simmer being careful not to let the tapioca stick to the bottom of the pan.
Put the yolks into a bowl and stir in some of the tapioca mixture to temper the eggs.
Then add yolks to the pan while stirring. Pour into a bowl and cool.
You can eat it warm (as I hear it is often served in the colder months) We like ours after it has chilled several hours in the fridge at any time of year.