Add milk, heavy cream, water, cocoa powder, erythritol, and cinnamon to a medium pot over medium-low heat. Whisk together frequently until the mixture heats up and starts to steam.
Step 2
Pour the chocolate mixture into a milk pitcher and froth with a frothing wand. Brew espresso in a mug and pour the frothed chocolate mixture on top. Garnish with a dusting of cocoa powder and serve.