For steaming and frothing milk together in mason jar:
-Put all 1 ¼ cup milk in a large mason jar or heat-proof container (it should only be half full), put the lid on, and shake the jar as hard as you can for about 30 seconds, until frothy.
-Remove lid and place the jar in the microwave for 45 seconds.
-Pour the steamed milk right into your espresso and spoon the froth on top.