1Melt the butter in a saucepan over low heat.
Add the cocoa powder and sugar to the melted butter, stirring continuously until well combined.
Gradually pour in the milk, stirring constantly to ensure a smooth mixture.
Break the dark chocolate into small pieces and add them to the saucepan.
Continue to stir the mixture over low heat until the chocolate is completely melted and the mixture is smooth.
Pour the mixture into a mold or a lined baking tray.
Allow the mixture to cool to room temperature, then refrigerate until set.
Once set, cut into bars and serve.