Line a 24cm spring-form cake tin with baking paper on the base and around the sides.
Combine the rice bubbles, icing sugar, cocoa powder and desiccated coconut in a bowl. Melt the copha in a saucepan over the stove or in a bowl in the microwave, and add to the mixed ingredients, stirring well.
Transfer the mix to the cake tin, pushing slightly with a spatula to compress. Place in refrigerator and chill for at least 30 minutes.
In a large bowl, combine Milo, milk, gelatine dissolved in water and cream cheese. Mix well until combined. Use electric handheld beaters to whip the mixture until light and airy.
In a separate bowl, beat the cream and castor sugar until thick. Carefully fold the cream mixture into the Milo/cream cheese mix, then spoon into the cake tin (on top of the chilled chocolate crackle base).
Tap the tin on the bench a few times to settle the mixture, then refrigerate for at least two hours before removing from cake tin. Dust with additional Milo and serve.