Whisk together the chocolate syrup, the milk and the peppermint extract to taste. Adjust the syrup and extract according to your taste. Keep it fairly sweet, as it won't taste as sweet after it is frozen. Pour half of the chocolate milk into one ice cube tray and freeze for at least 4 hours. Place the rest of the chocolate milk mixture in the refrigerator to chill.
Once the ice cubes are set, pour the rest of the milk into the blender and add the ice cubes. Puree until thickened and frothy. Pour into glasses, drizzle with chocolate and serve immediately*.
*The ice milk will start to separate if it sits too long.