In a blender, combine the milk, chocolate syrup, granulated sugar, unsweetened cocoa powder, and vanilla extract.
Add the ice cubes to the blender.
Blend on high speed until smooth and frothy. If the mixture is too thick, add a splash more milk. If it's too thin, add a few more ice cubes and blend again.
Pour the frozen hot chocolate into glasses.
Top with whipped cream and chocolate shavings, if desired.
Serve immediately and enjoy!
Notes
This recipe is easily customizable. Feel free to adjust the sweetness or chocolate intensity to your liking.