In a medium pot, simmer the cream, milk, sugar, salt and tea until sugar completely dissolves, about 5 minutes. Remove pot from heat. In a separate bowl, whisk the yolks until they're broken up.

Whisking constantly, slowly whisk about a third of the hot cream into the yolks, then whisk the yolk mixture back into the pot with the cream. Return pot to medium-low heat and gently cook until mixture is thick enough to coat the back of a spoon (about 170F on an instant-read thermometer).

Cool to room temperature. Strain through a fine-mesh sieve into a bowl and discard the tea bags and any scrambled egg bits that get caught in the sieve. Press out any liquid that might be held in the tea bags back into the custard.

Cover and chill at least 4 hours or overnight. Churn in an ice cream machine according to manufacturers’ instructions; it'll look like really thick whipped cream when it's done churning. Transfer to a container (I like to use a long, shallow container because it helps me get better scoops than a pint container), smooth the top and cover. Freeze until solid.

Fill a medium pot half-full with water, and bring to a rolling boil. Add the tapioca balls and cook until done, stirring occasionally to make sure they don't stick; they'll be shiny all the way through with no matte, dry starch anymore. If you're unsure, taste one; it should be chewy all the way through and not hard or powdery in the middle. The timing really depends on what brand you're using and how much water you have; I've had this take anywhere from 20 minutes to 2 hours, which is a huge window; I'd start at 20 minutes and check every 20 minutes after until they're ready.

When your boba is the perfect chewy texture, drain them.

Place the pot back over medium heat, and let any excess water evaporate. Once the inside of the pot is dry, add the brown sugar. Let it melt and cook it until it smells really caramelly. Add the water; be careful, since it will sizzle and bubble and hiss. Swirl the pan and cook until the sugar melts again and the syrup is homogeneous.

Add the boba, stir to make sure that the boba doesn't stick together, and lower the heat to medium-low. Cook for 20 minutes, or until the boba soaks up some of the syrup and the syrup has thickened.

Cool slightly, then spoon the warm boba and brown sugar syrup over scoops of the milk tea ice cream. Serve.