Cut the dark chocolate into small pieces and place it in a microwave-safe bowl. Melt the chocolate in the microwave. Do this in 20-second intervals, stirring after each interval until the chocolate is completely melted and smooth.

Scoop the vanilla ice cream into a bowl and let it sit for a few minutes so it softens slightly. This makes blending easier. Meanwhile, measure out the semi-skimmed milk and cocoa powder.

Add the vanilla ice cream, the semi-skimmed milk, the cocoa powder, and the melted dark chocolate to a blender. Blend briefly until the mixture is creamy and airy.

Pour the milkshake into tall glasses and serve immediately with a straw. Enjoy this delicious, refreshing drink. Enjoy!