In a small pot, add in the milk and tea bags. Bring to a simmer, turn off the heat, cover, and let steep for 10 minutes.
Use the back of a spoon to press the tea bags against the side of the pot to squeeze out all of the tea-infused milk before discarding the tea bags. Transfer the milk tea to a glass with a spout, cover, and let chill in the fridge.
Rinse out the pot and fill with about 1 inch of water. Bring to a rolling boil.
Add the tapioca pearls to the boiling water and immediately give it a stir to prevent the pearls from sticking together. Boil uncovered for 15 minutes.
Remove the pot from the heat, cover, and let sit for another 15 minutes.
In a small bowl, add the brown sugar. Use a slotted spoon to transfer the cooked pearls to the bowl of brown sugar, draining most of the liquid. Stir together, using the heat of the pearls to dissolve the brown sugar into a syrup. If it’s too dry, add 1-2 tablespoons of water.
In each serving glass, add about 100g of pearls with syrup. Fill the glass about ¾ or full with ice. Pour in about 300g of earl grey milk tea. Stir together well. Add any leftover brown sugar syrup to taste, if needed.