Prepare the oven by pre-heating at 180°C for at least 10 mins. Prepare the baking dish by applying oil/butter and then dusting it with all-purpose flour. Alternatively, it can be lined with a baking sheet.
In a bowl add all-purpose flour, baking powder, tutti frutti and a small pinch of salt. Mix well until the tutti frutti are coated well in the flour.
Add sugar and oil together and mix well. In another bowl, mix the thick curd with water and make it into a thick buttermilk. To this, add baking soda and vinegar. In a minute, the mixture becomes frothy. Add both these mixtures to the flour mix along with Vanilla Essence.
Gently fold until combined together. Pour the batter into the baking tin (fill it only to ¾th) and bake it for 30mins in the oven at 180°C. When a toothpick or knife is inserted, it should come out clean. Switch off the oven and let it stay in there for 3-5 mins. Remove the baking dish and cool it down. Invert the cake onto a plate. Cut into slices of desired width.
Serve sliced cake with a cup of hot coffee/tea. Store in an airtight container in fridge for upto a week.