To use a regular-sized blender, double or triple the recipe.
Any kind of milk can be used but whole milk will give you a creamier hot chocolate.
Homemade chocolate syrup can be made ahead of time and stored in the refrigerator. Once the syrup is made, it can be blended with the ice and milk.
The whipped cream can be made as stiff or soft as you like by adjusting the time you whisk. If you want a more pourable whipped cream with soft peaks that will stir into the drink easier, whisk until it thickens slightly. Make sure to move the handheld milk frother up and down to get air into the cream. To get stiffer whipped cream, whisk until you get medium or firm peaks.
Whipped cream can be made ahead and stored in the refrigerator in an airtight container for up to 2 days. Stir it a little since it may have deflated a bit.
To use hot chocolate mix instead of chocolate syrup, replace a packet of hot chocolate mix with the syrup in the recipe.