In a small saucepan over medium heat, add the water, sugar, and cocoa powder. With a whisk, stir to combine into a chocolate mixture. Add the milk and heat it up.
While the hot chocolate heats up, brew the espresso. Pour each espresso shot inside a mug. If using espresso powder, add 1 to 1 ½ teaspoons of espresso powder into each cup.
Combine:
Once the hot chocolate is warm, add the vanilla and stir.
Pour the hot chocolate over the espresso shots.
Serve:
Top the espresso hot chocolate with whipped cream.