Of the Takeaways i frequent all seem to have one thing in common,the lovely smell that emanates from their food does dissapear if you freeze their Curries for say a week then re-heat & most of it has gone, even eating the day after a large percentage of the smell has gone.
If you analyze the curry by eating it slowly & search for the different flavor's you will discover that it is only this strong smell that gives Bir Curries the edge over all our attempts.
Apart from this our home-made Curries are a million times better & i don't think the Bir's deserve as much credit as we give them.
my favorite Bir makes a very hot Tindalloo (their version of the mighty Phall) but no taste of Chillie powder,were as two other Bir's i visit make hot Curries but their Phall tastes very much of Chillie powder.
I believe that it is a seasoning or flavor enhancer that we all can smell,also, i ordered a Tindalloo & brought it home to discover a white powder on top of the Curry (it was Garlic powder) as we all know cooking our ground Spices does take the pungency out of them, therefore it may be true that seasoning is added to the cooked Curry just before serving then just stirred in,this would give rise to a strong smelling Curry would it not.
As always i do think were are there when it comes to cracking the Bir Curry but i also feel it is a seasoning or some additive that gives Bir's a sort of edge,this is also very logical looking at it from a business point of view.
Also if your looking for a Curry with depth try this mate you will be pleasantly surprised...
https://curry-recipes.co.uk/curry/index.php?topic=692.0