- Preheat the oven at 180 C / 350 F for 10 minutes. Grease a cake tin.
- Add white vinegar into the milk and mix. Leave this for 10 minutes. The milk will get curdled.
- Add oil and sugar in a mixing bowl. Mix till sugar melts.
- Now add the curdled milk (buttermilk). Mix nicely.
- Add vanilla essence and mix well.
- In a separate bowl, put a sieve and add all purpose flour (maida), cocoa powder and baking powder. Sieve. Add chopped walnuts and give it a mix so that the walnuts get coated with the flour mixture.
- Add the dry ingredients into the wet ingredients.
- Mix till a uniform cake batter is formed.
- Add the cake batter into the cake tin. Top it with chopped walnuts.
- Bake at 180 C / 350 F for 30-35 minutes or till a toothpick inserted into the center of the cake comes out clean.