Break the chocolate (150g) into pieces and melt it (either using short bursts in the microwave – stirring regularly, over the lowest possible heat in a saucepan – stirring constantly, or in a bain marie – stirring constantly).

Once melted remove it from the heat and pour into another bowl (this will help it to cool as it needs to be back to room temperature before mixing with the buttercream).

Beat together the dairy-free margarine (125g) and baking block (125g) until soft (it can take a bit of time to get it really smooth but persevere to ensure you get perfect buttercream). Add the vanilla extract (¼ tsp), cocoa powder (40g) and icing sugar (250g) and beat until fully combined (it’s easier to avoid the cocoa powder and sugar flying everywhere if you add it a spoonful at a time).

Once the chocolate has cooled to room temperature (DO NOT add the chocolate when it’s still warm as it’ll melt the butter and your buttercream will end up too runny) pour it into the buttercream and beat until fully combined. You should find that the buttercream is soft and spreadable.

Your buttercream is now ready to use.