Heat the oven to 190C/170C fan/gas 5. Line bun tins with paper cake cases. Put all the ingredients for the cupcakes in a large bowl using 4 tbsp of the orange juice, then beat together for 1-2 mins until smooth.
Spoon the cake mix into the cases, so they are three-quarters full. Bake for 15-18 mins or until golden and firm to the touch. Cool in the tin for 5 mins, then transfer to a wire rack.
For the icing, beat the butter, vanilla and icing sugar until pale and creamy, adding 1-2 tbsp warm water to loosen, if needed. Ice the cakes with a palette knife or use a piping bag to create swirls deep enough to hold the Santa and elf legs.
For the legs, make a batch of fondant icing following the pack instructions. Cut the candy canes and pencil sweets into 4cm lengths. Use green fondant icing to mould elf boots around the candy cane legs and black fondant icing to mould Santa boots around the strawberry pencil legs. Add some white fondant around the top of Santa boots. Use the made-up fondant icing to stick a silver or gold ball onto each toe of the elf boots. Let the boots dry completely. Use our chimney template, to make paper sleeves to wrap around the cupcake cases. Push the legs into the cupcakes just before serving.