1-In a medium saucepan over medium-high heat, combine the milk, unsweetened cocoa powder, granulated sugar, ground cinnamon, vanilla extract, chili powder, and ground cayenne pepper (if using).

2-Whisk the mixture and add the bittersweet chocolate.

3-Heat, continuing to whisk, until the chocolate is fully melted and the mixture is hot but not boiling.

4-Pour the hot chocolate into two mugs.

5-Serve immediately with optional toppings such as marshmallows, chocolate shavings, or a cinnamon stick.