Combine all ingredients except the optional whipped cream in a mason jar. Screw on lid and wrap top with the towel (in case your jar leaks). Give a few very good shakes, until everything is well-mixed and milk is foamy.
Pour into a mug and microwave for 30 seconds or until steaming. Top with whipped cream if desired. Enjoy!
Approximate nutritional information was estimated using non-fat milk and does not include whipped cream.