In a medium saucepan, pour in 2-3 cups of whole milk along with ½ cup of heavy whipping cream. Place the saucepan over medium heat, stirring occasionally until steaming.

In a separate bowl, whisk together ½ cup of high-quality cocoa powder and 1-2 tablespoons of grated milk chocolate. Gradually add about ½ cup of the hot milk mixture to the chocolate, stirring to form a smooth paste.

Slowly pour the chocolate paste back into the saucepan, whisking constantly. Add the sweetened condensed milk and ⅛ teaspoon of vanilla extract, stirring until fully blended.

Reduce heat to low and let the mixture simmer for about 3-5 minutes, stirring occasionally. Adjust thickness by adding more milk if needed.

Ladle the hot chocolate into mugs and top with whipped cream, then sprinkle with ground cinnamon and chocolate shavings.