Heat the water until hot but not boiling (in the microwave for 60 to 90 seconds or on the stovetop in a saucepan).
Add the chai tea bag to the hot water and let it steep for up to 3 minutes.
Add the milk to a tall, microwave-safe bowl or jar. Microwave for 30 seconds. The goal is to make the milk warm, but not hot.
Use a frother wand or manual frother to froth the warm milk. Set it aside for 1 to 2 minutes.
Remove the tea bag from the hot water and add the blue matcha powder and any sweetener (if using). Assess the color. For brighter blue, add a drop of blue food coloring (see notes).
Pour the frothed milk on top. Sprinkle more of the pea powder on top.
Notes
For the milk, I recommend soy milk because it makes the best froth. Otherwise, you can use your favorite plant-based milk but realize the frothy foam will not be as thick.Blue matcha powders come in varying shades of blue. You can add a drop of blue food coloring if you prefer a brighter hue.