Grease a round baking cake tin of 8×8 inches diameter with oil or butter and preheat the oven at 180 degrees celcius.
In a bowl take softened butter, add sweetened condensed milk and oil to it and beat till it is light and fluffy.
Next for the dry ingredients seive whole wheat flour, cocoa powder, baking powder, baking soda, salt and mix everything well.
Add the sifted dry ingredients to the wet ingredients.
Add orange zest, vanilla extract, milk and beat nicely to form a smooth lump free batter.
The batter should be smooth flowing consistency if its thick add little more milk and adjust the consistency.
Now pour the cake batter in greased tin and tap the sides.
Bake the chocolate cake in a preheated oven at 180°C for 25 minutes. Do check the cake after 20 minutes as the temperature vary from oven to oven.
Once done check the cake with a toothpick. If it comes out clean the cake is perfectly baked.
Let the cake cool down completely meanwhile make the chocolate ganache.
In a saucepan take amul cream and just bring it to boil.
Pour the cream over dark chocolate and leave it undisturbed for 10 minutes.
After 10 minutes add butter (room temperature) and mix untill smooth chocolate ganache is formed.
Once the cake has cooled down pour the chocolate ganache evenly over the cake sprinkle some edible golden dust from top. The chocolate cake is ready cut in slices and Serve!