Take a grinder and Grind both the biscuits separately into the powder.
Mix both the powders in a bowl.
Add powdered sugar mix it well.
Now add lukewarm milk gradually (You can take more or less milk as per your requirement). Keep on adding milk until you get the proper consistency and make sure there are no lumps in it.
Now add Vanilla essence and mix it well.
Take a pressure cooker and keep it on flame then take a mould and keep it in a center of cooker. Now pour 2 glasses of water in it and let the water boil. Make sure that the water should starts boiling before placing the mould (filled with batter) in it.
Grease the mould with butter and keep aside.
In the Very end add Eno and combined it well. Mixture looks Fluffy. At this time does it quickly and drops the mixture into the Greased mould.
Place your mould very gently in the pressure cooker. Remove the whistles of pressure cooker and cover the lid on high flame and cook a cake for 20 mins.
After 20 mins keep the flame on low for 3 mins.
Now turn off the flame and open the lid.
Insert a tooth pick or knife just to see if it is cooked properly or not. If the Knife comes out clean it means the cake has cooked properly.
Take out the mould from pressure cooker and let it cool.
Scratch the sides of pan and unmould.
Soft and Spongy Buiscuit Cake is ready to serve.
1) Make sure that the water should starts boiling before placing the mould (filled with batter) in it otherwise it will take time to cook and cake will not become spongy. 2) After adding Eno fruit salt do not keep batter for long time otherwise Cake will not be spongy.