I bought yet another BIR chicken korma last night and made a key observation, thanks to the open plan kitchen. The dish was very 'representative' of a typical BIR korma.
And I bought yet another one, from a different place, this weekend! My observations are only partial. The proprietor kept me busy talking, but every little observation helps, I hope.
First, the chef added a lump of solid yellow-ish fat to the pan. I guess this was butter ghee, veg ghee or, less likely, butter or margarine. I'd estimate about 2 ozs. As always, the flame was on full blast the whole time.
Then he added 'quite a bit' of a white liquid. I would hazard a guess that this was a pre-mix of evaporated milk, coconut powder, sugar and any other ingredients, like in Terry's korma masala mix.
There followed a ladle of base sauce. All the above elements were added in fairly quick succession. Once that lot had heated through, he knelt down to get some ingredients from low down on a storage rack, so I couldn't see properly. But it included pieces of pre-cooked chicken, which looked quite yellow and perhaps some additional yellow colouring, too. He could have added extra spices at this point. I don't know.
Then he poured in 'quite a bit' of UHT single cream, straight from a carton, so there was no mistake what that was. I'd say somewhere between 65 and 130 ml. At the end of the day I ended up with a large take away carton full of korma, so the sauce volume has to come from somewhere. I never saw him add more than the initial ladle of base sauce.
Finally, he added 'a bit' of coconut milk from exactly the same type of tin you'd get from any supermarket. I'd estimate 45ml (three tbls) of coconut milk. So, if there was coconut powder in the pre-mix, that's a double dose of coconut.
This was heated/boiled for about 2 or 3 minutes longer and the korma was complete.
Again, it was typical of a BIR korma.
I hope this helps.
Regards
George