Grease a 150 mm. (6") diameter shallow microwave safe dish using soft butter. Line it with a piece of greaseproof pepper at the bottom of the dish and again grease it using a little soft butter.

Sieve the plain flour and baking powder and keep aside.

Combine the curds and baking soda in a bowl, mix well and keep aside.

Combine the butter, sugar and ¼ cup of hot water in another bowl and mix well using a whisk.

Add the curds-baking soda mixture, plain flour-baking powder mixture and vanilla essence and mix well to make a smooth batter.

Remove from the microwave and keep aside to cool for 5 minutes.

Loosen the edges with help of a butter knife and unmould. Remove the butter pepper and discard it.

Use as required.

I used this Vanilla Sponge Cake with chocolate fondue.