To a medium saucepan, add the milk, sugar, and cocoa powder. Place over medium-low and cook, whisking constantly, until the sugar has dissolved and the milk is heated through. (Don't let the milk scald.)
When the edges of the chocolate milk begin to foam, pour in the coffee/espresso, mint extract, and vanilla extract. Whisk to combine. Cook until the mocha is steaming and the edges are frothy.
Pour the mocha into two coffee mugs. Garnish the tops with whipped cream, chocolate shavings, and crushed peppermint if desired. Serve warm.
Notes
Nutritional information if for the mocha only and does not include toppings.