Preheat oven to 180 degrees. Grease a 13 x 9 inch pan and set aside.
In a large mixing bowl, sift in the dry ingredients from flour to salt. Add the sugar and give a good mix.
In a pitcher, whisk the milk, oil, eggs and vanilla till homogenous.
Add into the dry ingredients and fold till combined.
Add the coffee into the boiling water and add into the batter. Beat to combine.
Pour into prepared pan and bake for 40 minutes or till skewer comes out clean.
As soon as the pan is out of the oven, poke holes all over the cake. Drizzle the condensed milk evenly all over the cake.
Allow the cake to soak up the milk, let it cool and then keep in the fridge, for around an hour.
Whip the cream and icing sugar till stiff. Fold in the malted chocolate powder, if using.
Spread the cream over the cold cake. Grate the chocolate over as needed. Allow it to refrigerate till serving time.