Preheat the cooker/ kadai for 10 minutes with salt in it on a medium flame.
Roughly break the biscuits and add it to the food processor along with the sugar. Blitz until there are no chunks remaining and it's a homogenized fine mixture.
Transfer the biscuit mixture to a glass bowl, add in the baking powder and mix well.
To the bowl now add the milk. Mix until everything is well combined and the batter looks nice and smooth.
Generously grease the 4’ inch baking pan with butter. Line it with a butter paper.
Transfer the batter in the pan and carefully place this pan in the cooker/Kadai on top of the wire rack. Cover the cooker/Kadai with a lid and cook the cake for 20 minutes until a skewer inserted comes out clean.
Once done cooking, carefully remove the cake and let it cool completely before unmoulding.
For decoration, apply whipping cream and melted dark chocolate over it. Garnish with chocolate sticks and gems.