Hi Phil. Wasn't aware of any issues with oil and a pressure cooker. I haven't experienced any so far. Will look into it.
For the Chargha quarters put the steamer basket thingy (BIR supplies thread) into the empty pressure cooker. Then poured in about 2/3 cup of water. Marinaded 8 h (drained off) chicken quarters are then placed in the basket. 15 mins cooking time when up to pressure (90 Kpa). Adjust time depending on amount of chicken. Small chicken (about 1.1 kg) used here. The same method is used for the Manchester tandoori chicken starter, except I find it looks better if cutting slits into the chicken for this is done after it's been cooked (because of the shed-load of red food colouring). Cut slits into the chicken for the Chargha prior to adding marinade, as is done usually.
I let the pressure cooker depressurise by itself. Then remove the basket to cool. There's typically about an inch of stock now in the pressure cooker. The basket thingy has little feet, so the Chargha hasn't been sat in the stock during cooking; not much of it anyway.
I reuse the stock immediately to make the 'Chargha' chicken wings. No basket. Add remaining Chargha marinate to the stock and mix in 1 heaped tbsp of Kashmiri chilli power. A fair few green cardamoms (optional). 1.2 kg skin-on fresh chicken wings. Mix everything up for a couple of minutes. Then 15 mins at 90 Kpa.
The pressure cooker I have is the stainless steel Amazon Basics one.
Rob