In a 5 ltr pressure cooker add oil and add butter. Mix and add corns,salt and turmeric powder nicely such that all the corns get coated with butter, salt and turmeric.

Now close the lid removing the whistle. After few mins, you will hear a popping sound. At this stage, lower the flame and without opening the lid just shake the cooker a bit, two to three times. This will make our popcorns pop evenly coated. As soon as you hear that no sound can be heard, immediately switch off the gas. Open carefully are your popcorns are ready to hog!!

Notes
if you have a smaller cooker then you try with one fourth cup corns first.You will have to check how small your cooker is accordingly decide the quantity of corns.The bigger the better because after they pop up they cover up till top edge of the cooker.
Quantity of salt you have to see as the butter you will use will also be salty
If after making you feel they r little less salty,no worries sprinkle some chaat masala.They will become chatpata popcorns!!