Brew espresso or strong coffee as desired.

Pour milk into a mason jar with chocolate syrup and peppermint extract. Microwave for 1 ½ minutes, adjusting time as needed to heat without boiling.

Carefully remove the jar of milk from the microwave using a towel or potholder. Place the lid on the jar and shake vigorously for 30 seconds to 1 minute.

Remove the lid carefully, being aware of any pressure that may have built up.

If desired, drizzle chocolate syrup in the mug. Add the espresso and pour in the chocolate milk mixture, topping with any remaining foam from the jar. Serve immediately with whipped cream and additional chocolate drizzle or crushed peppermint candies, if desired.