Heat the Milk: In a medium saucepan, heat the full cream milk over medium-low heat, stirring occasionally to avoid scalding.

Melt the Chocolate: In a separate, heatproof bowl, add the chopped Belgian cooking chocolate. Once the milk is warm (not boiling), pour it over the chocolate and let it sit for a minute to melt.

Combine: Stir the chocolate and milk mixture until fully combined and smooth.

Thicken the Mixture: In a small bowl, mix the cornstarch with a few tablespoons of cold milk to create a smooth paste. Gradually add this to the chocolate mixture while stirring continuously.

Add Cocoa: Stir in the cocoa powder, adjusting the sweetness with sugar if desired. Keep stirring until the mixture thickens to your liking (around 5–7 minutes).

Serve: Pour into mugs and top with whipped cream and marshmallows if desired. Enjoy your rich, creamy indulgence!