01 - In a small saucepan over medium heat, combine milk, chopped chocolate, cocoa powder, sugar, cinnamon, nutmeg, cayenne pepper if using, and salt.
02 - Whisk continuously until chocolate is fully melted and mixture is smooth and steaming, approximately 5 to 7 minutes without boiling.
03 - Remove from heat and stir in pure vanilla extract.
04 - In a chilled bowl, whip heavy cream, powdered sugar, and vanilla extract using a hand mixer or whisk until soft peaks form.
05 - Pour the hot chocolate into serving mugs.
06 - Top each mug generously with prepared whipped cream.
07 - Sprinkle with ground cinnamon or chocolate shavings if desired and serve immediately.