Boil 1 cup water and add to a liquid measuring cup (use a measuring cup large enough that can hold the addition of the milk). Cut the vanilla bean in half and add it to the boiling water along with the tea bags and steep for 5 minutes.
Add the brown sugar and vanilla extract, stir until dissolved. Add the milk and stir. Chill this while you make the boba.
Place boba pearls in a small pot and cover with 2 inches of water. Bring to a boil and cook until all the boba float to the top.
Strain boba to remove water and divide evenly between two glasses. Add ice to each glass, then divide the tea mixture between the two glasses.
You can also make this as one larger serving, you may want a little less boba, but the process is the same.