Grease & line two 20cm (8 inch) round spring-form baking pans.
Cake
Place a medium sized bowl over a saucepan containing water. Heat saucepan over medium heat.
Add white chocolate, butter, caster sugar, milk & vanilla extract to bowl.
Heat while stirring regularly until all ingredients are melted, blended and smooth. Remove from heat and allow to cool for a few minutes.
Add eggs and stir until fully combined
Add self-raising and plain flour to bowl and fold through until fully combined.
Pour mixture evenly into the two baking pans.
Place in oven and bake for approx 60-70 minutes or until a skewer inserted into the centre of the cake comes out clean.
Remove from oven, let cool in pans for approx 10 minutes before turning out onto wire racks to cool completely.
Buttercream
Add milk to a small saucepan over medium-low heat. Heat until milk is warm.
Add malted milk powder and continuously stir until a smooth paste is formed.
Remove from heat and place in refrigerator for about 10 minutes to cool.
Add butter and icing sugar to a bowl and using an electric mixer beat until light and fluffy.
Add malted milk powder mixture and continue beating until fully combined.
Cake Assembly
If needed, trim tops of cakes to level them out.
Cut each cake in half.
Place one cake layer, as the base layer, onto a plate or stand.
Spread approx 1/4 of the buttercream over the base layer. Note: the cake will be spread with 3 layers of buttercream (1/4 per layer) with the remaining 1/4 reserved for the final layer over the top and sides of the cake.
Top with the next cake layer and spread with buttercream. Repeat until final cake layer is placed on top.
With the remaining 1/4 of the buttercream spread a thin layer over the top with most of the buttercream spread around the side of the cake.
Place in refrigerator for about 30 minutes to chill.
Remove from refrigerator and pour and spread cooled ganache (see instructions below) over the top of the cake, Set cake aside for a few minutes to allow ganache to set a little
Add malted biscuits and peanuts to a small bowl and mix to combine.
Sprinkle biscuit and peanut mixture over the top of the cake. Optionally add some Maltesers to the top as well for decoration.
Chocolate Ganache
Place a medium sized bowl over a saucepan containing water. Heat saucepan over low heat.
Add dark chocolate and cream to bowl. Stir regularly until mixture is combined and smooth.
Remove from heat and allow to cool for about 10 minutes or so but not set.