One 14oz tin of evaporated milk (about 400g)
1 tbsp butter
3 tbsp unsweetened cocoa
Add all ingredients to a pan and reduce on a medium heat for about 10-15 minutes, until you can see the bottom of the pan when you drag a wooden spoon through it. Leave to cool until you can handle it, then roll into small balls between well-buttered hands and roll in chocolate sprinkles.