Place the butter, chocolate, cream and vanilla in a small pot and gently heat while stirring until melted and smooth. Meanwhile, sift the cocoa powder and icing sugar together in a separate bowl. Whisk into the melted chocolate mixture until smooth and combined. If your mixture looks a little lumpy, you can pass it through a sieve.

Pour the fudge icing mixture into a bowl and cover the surface directly with cling film. Chill for 1-2 hours or until it becomes a thick, spreadable consistency.

The fudge frosting will set firmly if chilled for too long. To bring it back to a usable consistency, gently heat it in the microwave in one or two 10-second bursts until softened. Be careful not to melt it again!

Spread the fudge frosting over your favourite cake or place into a piping bag to decorate cupcakes.

Tip: This recipe makes enough frosting for a 20cm round or square cake, one 21 x 11 cm loaf cake or about 6 cupcakes. 

For a lighter consistency and colour, whip the chilled and thickened fudge frosting with an electric hand mixer for a minute or two before using.