Place milk into the Vitamix container and secure the lid. Select the lowest setting. Start the machine, slowly increase to Variable 6, and run for 30 seconds. (If only making a half recipe for a single serving, reduce run time to 15 seconds.) Stop the machine and remove the lid. Add chai tea. Secure the lid, select Variable 8, and Pulse 3 to 5 times to incorporate. Place 1 cup of ice into each 16-ounce (480-ml) cup. Pour the latte into each cup, then top with a pinch of cinnamon. Sweeten if desired.