Take raisins in a bowl and add hot water in it.
Soak them for 30 minutes.
Transfer the raisins, along with the water in which they are soaked, in a blender jar.
Blend them into a fine puree.
Transfer the puree in a bowl.
Add oil and vinegar.
Give a good mix.
Put a sieve over the bowl.
Add flour, baking powder, baking soda, cinnamon powder, salt and raisins.
Sift them into a bowl.
Mix by using cut and fold method. Here if you feel that batter is slightly thick, you can add bit of the water, just spoon by spoon.
Add raisins.
Mix them too.
Pour the batter in 6 to 8 inches baking tin lined with greased butter paper.
Bake in preheated oven @180°C for 40-45 minutes.
Check by inserting a toothpick, if it comes out clean, it's a sign that cake is properly baked.
Let it cool down a bit for 15-20 minutes.
Take the cake out of pan and let it cool down completely on cooling rack.
Enjoy after slicing.