In the meantime, arrange a butter paper at the base of 6 inches cake tin and grease the tin with oil.
When chocolate solution turns completely cool, put a sieve on the bowl.
Add all purpose flour, cocoa powder, baking powder, baking soda and salt.
Sift the dry ingredients into the bowl.
Add vanilla essence.
Mix. Make sure there remains no lumps.
Transfer this batter in a greased cake tin.
Tap the tin few times so that there remains no air bubbles.
Bake in a preheated oven @180°C for 35-40 minutes.
Check by inserting a toothpick and if it's come out clean, its a sign that cake is thoroughly baked. You may spot some chocolate on toothpick but that is most likely a melted chocolate.
Place the cake tin on wire rack and let it cool down a bit for 15-20 minutes only. Don't wait to let it cool down completely.
Invert the cake.
Now let the cake cool down completely. If you like, you can stop the process here and start enjoying the cake. But we will go ahead to make it super chocolate-y.