In a small saucepan over medium heat, combine the milk and cocoa powder. Whisk continuously until the cocoa is fully dissolved and the mixture is warm (but not boiling).
Stir in the brown sugar, molasses, ground ginger, cinnamon, nutmeg, vanilla extract, and a pinch of salt. Continue to whisk until everything is well incorporated and the mixture is creamy.
Lower the heat and allow the hot chocolate to simmer for about 2-3 minutes, stirring occasionally to prevent sticking.
Once warmed to your desired temperature, remove from heat and pour into mugs.
Top with a generous dollop of whipped cream or marshmallows.
Garnish with crushed gingerbread cookies for an extra festive touch.