Sift maida flour, baking powder together so they are mixed well. i.e. 3 to 4 times
In bowl add refined oil, butter, powdered sugar and beat them well. Once they are mixed well add the egg and beat well. Now add the baking powder maida flour mixture slowly and beat well. Once they are mixed well vanilla essence, milk as need and make a batter consistency to dosai batter.
Coat the pan which comes with pressure cooker (refer image below) ghee and pour this batter.
Heat the pressure cooker and place this pan inside. Cover with out the whistle. Bring the heat to simmer and bake this for 45 minutes approximately or until the cake is cooked (If you insert it into the center of the cake, it should come out clean, with no streaks of batter.) and serve.