Freaky finger red velvet cake

Ingredients

For the red velvet cake
175g soft butter

, plus extra for greasing
225g white caster sugar
1 tsp vanilla extract
3 large eggs

, at room temperature
1 tbsp red food colouring paste (we used Christmas red from Sugarflair)
200g plain flour
50g cocoa powder (we used Green & Black's)
1½ tsp bicarbonate of soda

½ tsp baking powder

¼ tsp salt
150g pot low-fat plain yogurt

, loosened with 2 tbsp milk
For the fingers and frosting
about 3 x 114g boxes white chocolate fingers (we found them in Tesco)
140g icing sugar
2 tsp milk

small blob of red food colouring paste
100g soft butter
300g full-fat cream cheese, fridge cold (we used Philadelphia as it has the firmest texture)
zest 1 orange

(optional