Thanks
Some useful pointers. I'll make chilli heads of them yet!

Normally I don't give supermarket ready meal curries the time of day (does anyone out there really like CTM?) but the one exception I really like is M&S chicken piri piri. I have tried to copy this using the ingredients list as a guide but I am still not getting there. It has a particular intense sweetness which I have been unable to recreate. One of the ingredients is given as molasses but the addition of sugar molasses does not help. I thought I had it cracked when I read about pomegranite molasses being a secret ingredient in middle eastern cookery but this didn't do the trick either.
Does anyone else like this curry? If there are other fans help in duplicating this dish would be appreciated

This is a recipe based on one I obtained from the Tandoori trade magazine at least 7 or 8 years ago. It was claimed to be a domestic recipe rather than a BIR one and I have modified it with the addition of a restaurant style base sauce and omitted some rather tedious parts (pulping onions and separating the juice from the pulp by straining through muslin). I have also cut the quantities to serve 2 or 3 persons.

It is without doubt the best restaurant style curry I have made in 10 years. It has 'the smell' although it is not as pungent as with a genuine restaurant curry.

4 small onions
1 potato
rapeseed oil (skimmed from a previous recipe if possible)
2 heaped teaspoons chopped garlic
2 bay leaves
2 teaspoons chopped fresh ginger
4 green cardamoms
1 teaspoon black peppercorns
2-3 inch Cinnamon stick
6 cloves
1 fresh chilli (red or green)
1 teaspoon turmeric
2 chopped fresh tomatoes
1 tablespoon of ghee or butter
1/2 teaspoon sugar
chicken stock
1/2 teaspoon garam masala
salt (unless commercial stock is used)
restaurant style base sauce
chicken  (or lamb or prawn etc)

Very finely chop one of the onions (I usually blitz it in my Kenwood mini chopper) and fry in  oil until soft. Put the onions to one side.
In more oil fry the garlic and bay leaves and after two minutes add the cinnamon stick and cardamoms. After a further two minutes add the peppercorns, cloves and chopped chilli. After another minute add the ginger and turmeric and stir until well mixed in. Then add the potato, tomatoes and chicken followed by the ghee and sugar. Cook for 5-10 minutes then add reserved onions and desired quantity of base sauce. Add the stock and the remaining onions cut into quarters and the salt. After a couple of minutes transfer the whole thing to a casserole dish, add the garam masala and cook in the oven for about ?30 minutes.

Please note the following:

I don't usually measure ingredients or time cooking. I just do what feels right at the time. Not very scientific but I am trying to learn to cook via feel rather than rote.

There is no secret recipe for the base sauce. The one I use is similar to many posted on this site although I do add a small quantity of chilli, and gram masala so that it could almost be used as a very mild curry sauce in it's own right.

I have recently found that my curries have improved by using the cheapest supermarket cooking oil which is invariably rapeseed oil. Previosly I had always used corn oil or sunflower oil. No doubt restaurants also use the cheapest oil available.

I believe that re-using oil helps with 'the taste' and 'the smell'. This technique has already been mentioned in other posts and definitely does help.

The first time I made this I didn't notice 'the smell' till I came into the kitchen the next day and opened the dishwasher which had stood all night with the dirty dishes in it.
The second time I made this I reserved the skimmed oil and used it for the third occasion. I have some reserved oil from the third occasion in a jar in my fridge and the aroma is just delightful. There is no doubt that it is 'the smell'. It is like standing in the street behind your local BIR.

I think it is interesting to note that there is no cummin or coriander in this recipe although there is a possibility there is a tiny quantity in the base sauce. I have been using a batch from the freezer and can't quite remember what went in it. I will have to start keeping records as I usually modify my recipes each time in the search for improvement.

My garam masala is from 'Indian Cooking' by Sameen Rushdie. Spices are whole roasted and ground.

green cardamom
black cardamom
black cumin
cinnamon stick
black pepper
cloves
bay leaves
nutmeg
(mace omitted as I had none)

I would be grateful if someone could try this recipe and see if they too have a similar success with 'the smell'. I am not saying that I have cracked this. The aroma is definitely there but not as concentrated as with BIR dishes. In my own cooking it is another small step along a long road. If others think that there is something in this it will debunk the secret ingredient theory once and for all and confirm what others have said already, that it is technique and methods which count. My own goal is not to cook exactly like a restaurant but to come up with a way of domestic Indian cooking which mimics good restaurant style and ultimately surpasses it.

If no one else can reproduce these results then it means that either I am exaggerating the success of this recipe or that it is my own technique which is contributing rather than the ingredients. I would love to know which.

Please therefore give it a go and let me know the outcome.