Whisk together the coffee, 1-2 tablespoons of the sugar (depending on how sweet you like your coffee), cocoa powder and ½ teaspoon of the vanilla in a medium saucepan over medium high heat.
Continue whisking as it comes to a boil then remove it from the heat.
Heat the milk in a microwave safe bowl for 1 ½ minutes then use an immersion blender or battery frother and froth it until it starts to form little bubbles.
Whip the heavy cream and remaining vanilla in a medium bowl together until it starts to thicken then add the remaining tablespoon of sugar to the heavy cream and whip until stiff peaks form.
Optional: add the whipped cream to a piping bag or a large Ziploc bag with the end cut off with a Wilton2M piping tip.
Pour the coffee into a mug, pour in the milk then dollop on the heavy cream or pipe it into a swirl.
Garnish it with chocolate shavings and chocolate syrup if desired then serve.
Notes
Storing: While this drink is best served immediately, you can store any leftovers in the fridge for 1-2 days. Reheat or serve over ice. Freezing: You can freeze any extra coffee base without the milk mixed in ice cube trays. Use it to flavor iced coffee or to blend with frozen coffee drinks.