In a medium saucepan, combine 2-3 cups of whole milk and ½ cup of heavy cream over medium heat. Stir continuously until the mixture is steaming but not boiling, about 5 minutes.

While the milk and cream heat, whisk together ½ cup of cocoa powder and 1-2 tablespoons of grated milk chocolate in a bowl. Gradually add some hot milk mixture to this blend, stirring until smooth.

Pour the chocolate mixture back into the saucepan with the steaming milk. Add in the sweetened condensed milk and vanilla extract, stirring until fully combined.

Lower the heat to a gentle simmer, stirring frequently for about 3-5 minutes until thick enough to coat the back of a spoon.

Ladle the hot chocolate into mugs and top with whipped cream, ground cinnamon, or chocolate shavings. Serve immediately.