In a big bowl, break the biscuits into 4 pieces, each. And put it aside.

In a pan, heat the butter on medium low heat. Add the cocoa powder, milo powder, condensed milk, salt, hot water, egg and vanilla essence. Stir occasionally until all the mixture is melted. Then, remove the mixture from the heat. Add the biscuits and mix it until the chocolate sauce is well combined with the biscuits. Then transfer the biscuit mixture into a round baking pan. Press the top until the surface is flat and chill it in the refrigerator.

For the chocolate ganache, in a bowl, break the dark chocolate bar into small pieces. Then, heat the whipped cream in a pan. When it starts to boil, turn off the heat and pour the hot cream into the bowl of chocolate. Keep stirring until the chocolate is melted. Add the butter and vanilla essence and stir until everything is well mixed.

Pour the chocolate ganache into the biscuits mixture, and chilled it in the refrigerator.