Place the chocolate cube into a tiny small, microwavable dish or onto a piece of baking paper.
Heat for a few seconds in the microwave (medium setting) until softened/melted.
Add the chilli powder and mix through thoroughly. Form into a blob on a small piece of baking paper.
Place in the fridge to set.
Prepare an 8 inch square cake tin by completely lining with cling film (so that it hangs over the sides) and on top of this, base-line with non-stick baking paper.
Place the butter, dark chocolate, golden syrup and cocoa powder into a large, microwaveable/heatproof bowl.
Microwave on medium heat at 30 second bursts stirring between each, to melt all the ingredients until completely blended and smooth. (Alternatively, heat in a saucepan over a low heat, stirring frequently).
Set aside and allow to cool slightly.
While cooling, prepare the biscuits by either breaking into smallish pieces with hands or bashing (in a clean food bag and using a rolling pin). Alternatively, cut into thin sticks with a sharp knife. Set aside.
In a large bowl, mix together the chocolate mixture, biscuit pieces, M&Ms, frozen mini marshmallows and vanilla extract.
Tip the mixture into the cake tin and push to the sides, so that it is evenly spread. It will look quite lumpy on the surface.
Mentally divide the square into a grid 4 x 4 and using a teaspoon, carefully scoop up a little mixture from one of the grid pieces and place the chilli trick into the mixture, replacing the scoop on top to hide the trick.
Place the rocky road in the fridge for a couple of hours until fully set.
When set, remove the Rocky Road from the tin and peel off the clingfilm and baking paper.
Place on a clean cutting board.
Melt the white chocolate in a small microwavable (I use glass) bowl, on medium heat at 30 second bursts, stirring between each until melted and smooth (or place the bowl over a saucepan of simmering water, stirring frequently).
Add a little food colouring paste to the chocolate and mix thoroughly.
While still runny, drizzle the (now orange) white chocolate over the Rocky Road randomly with a spoon.
While the chocolate decoration is still unset, top with a few extra M&Ms and mini marshmallows.
Leave to set in the fridge.
* Note: nutritional information is an estimate & may vary according to portion size/ingredient variants.If you prefer, substitute M&Ms for any other colourful Halloween-friendly sweets.For younger children make Halloween Rocky Road child-friendly. Maybe pop in a chocolate that has been infused with lavender or Parma violets. Or add a piece of Turkish delight, a jelly ‘eye’ or a glacé cherry for a more oogly or unexpected texture.