Line a 8 x 8in pan with baking paper, making sure to hang the paper over the sides as this will help with easy removal when it is time.
In a large bowl, sift in the powdered sugar / icing sugar and cocoa powder.
Whisk to combine.
Melt the butter using a saucepan pan over medium-low heat. Or, the butter can be melted in a microwavable jug in the microwave. Heat in 30 second increments, stirring in between until melted.
Pour the melted butter into the cocoa mix.
Add the milk and the vanilla to the bowl and blend with a hand mixer to combine.
Quickly pour the mixture into the prepared pan. You need to move fast here as the mixture will start to set rather quickly after being mixed.
Place in the pan in the fridge for at least one hour to set.
Once set, lift the fudge out of the pan using the overhanging paper to help you.
Nutritional information is an estimate and provided as a courtesy. The values may vary according to the ingredients and tools that are used. Please use your preferred nutritional calculator for more detailed information.