Cook on low for 2 and a half hours. Stir twice during cooking.
Notes
For best results, stir twice during cooking. This will prevent everything from separating. However, if that isn't an option, then just give it a good stir before serving.
If you don't want to make this in the slow cooker, then you can follow this exact recipe on a hob. Cook on a low heat, stirring often.
To give the hot chocolate some frothiness, then whisk really well before serving.
Make sure to use whole milk, as it's what helps to make the slow cooker hot chocolate really thick and creamy.
Use the best quality chocolate you can, as you really will be able to taste the difference.
Add a pinch of chilli powder to your hot chocolate for a little kick of heat.
Add even more of a chocolate flavour with a couple of tablespoons of cocoa powder mixed in.