Step 1- Place the sugar and 1/2 cup of water in a pan over medium-low heat. Stir until the sugar dissolves, then simmer for 2 minutes until it slightly thickens. Keep your eye on the pan.
Step 2 - Thinly dice your milk or dark Cadbury chocolate. Then add it into the pan, with your sugar and water, and stir until fully melted and combined.
Step 3 - Then, whisk in cream, cocoa and 1/3 cup milk. Once fully combined, turn off your oven, and leave it in the pan for now.
Step 4 - Whilst waiting, get out the amount of cups or mugs needed, and pour in heated, and warmed milk.
Step 5 - Once you have completed the warm milk, and its ready in the cups/mugs, pour in your delicious, liquid, chocolate mixture and pop in a few marshmallows.
Step 6 - Allow them to melt, forming a thin frothy layer on your hot chocolate.
Step 6 - If you wish, add whipped cream to the hot chocolate. Complete with a dusting of cocoa.