Lay parchment paper on the cake pan with sides overhanging.
Break biscuits into coarse pieces. Not too big and not too small.
If you cannot find any Marie Biscuits, you can use Graham Crackers.
Any crackers or biscuits will work as long as they are not sugary, neutral flavor and have a snap when you break them.
You probably will not use all 400g too.
Set the biscuits pieces aside.
In a skillet over low heat, melt butter.
Once the butter has completely melted, add in condensed milk.
Whisk to combine well.
Add in cocoa powder and whisk to combine well.
Add in milo and whisk to combine well.
Add in hot water and whisk to combine well.
Remove from heat and whisk in the egg.
Once the egg has fully incorporated, return back to the heat.
Add in salt and 1/2 TSP of vanilla paste.
Whisk to combine well.
Add in 1 handful of the biscuit pieces.
Fold to coat the biscuits well.
Add another handful, folding and coating the biscuits well.
Keep adding, folding and coating until the biscuits do not have much sauce to coat.
Stop adding in the biscuits.
*You will have to judge. If the biscuits are less than the sauce, you will not get a beautiful outline as you slice the cake. If the biscuits are too many, it will not hold it's shape well when chilled.*
Transfer into the cake pan, distributing to the edges, making sure all corners are well covered.
Using an offset spatula, press to compact the biscuits mixture.
*It is okay to use a bit of strength as the biscuits have softened during the cooking process.*
Chill in the fridge to set.
In a sauce pot over medium heat, add cream.
Bring it up to a boil.
Remove from heat and pour into a large bowl of chocolate and butter.
Set aside for a couple of mins.
Stir to combine well and until the chocolate has completely melted.
Add a pinch of salt and 1/2 TSP of vanilla.
Give it a final stir to combine well.
Pour this chocolate ganache over the biscuit layer.
Swirl the cake pan to distribute the ganache evenly.
Give it a few taps on the counter to remove any excess air bubbles.
Chill in the fridge overnight to set.
Unmold and dust with raw cacao powder and milo.
Slice to trim off the edges.
Slice and serve immediately.
