In a bowl take flour, cocoa powder, baking soda and baking powder and sift a couple of times. Keep aside.
In another bowl, take milk at room temperature. Add vanilla essence and sugar to it. Whisk well to dissolve sugar.
Add dry ingredients to the milk and mix gently.
Grease a 8 inch round baking tray, lined with a parchment paper.
Pre-heat the oven at 180 C.
Add vinegar to the cake mix just before pouring in the baking pan and mix gently. Pour in the greased pan.
Bake at 180 C for 35 - 40 minutes till the toothpick inserted comes out clean.
Mine got done by 35 mins.
Let the cake cool in pan for 10 minutes.
Transfer it to wire rack to cool completely.