Mikka ,
I have said in previous posts , before I started eating Indian I was into Chinese food for years and one T/A seemed to be the best of the lot around here , the food had a particular flavour similar to the other T/A I used but just better . Everything that came from this T/A had this deeelicious flavour and for ages I would try to copy this flavour in my own cooking - but never did , me and the family used to sit down in serious discussion trying to fathom out what this ' special ' flavouring was

one day we were eating a meal from this T/A when it occurred to me that even the Chips had this ' special ' flavour so in my mind it must have been the flavoured oil they were using

Thank's to this forum I can now turn out a Madras which is better than our local Indian T/A
and personally I don't think there is any 'Secret ' ingredient that gives that special flavour but I do believe the flavoured / recycled oil is the answer.