About a year ago I asked in my local take away what ingredients went into Ceylon,  that was because they asked me how to make bread pudding, so I told them and then plucked up the courage to ask them about the Ceylon curry.  She muttered a few ingredients that were the norm and then added that molasses were used.  Molasses are sugar!   Maybe this is what we are missing.

I've been using sugar for a while now, I think quite a few of us do.

Molasses sometimes refer to a darker, more natural, less purified type of sugar. This has a different flavour to white sugar and could be well worth trying. I've been meaning to use that kind of sugar in my attempts at BIR chicken korma, since I'm sure BIR kormas have a taste which is sweet with a hint of toffee or fudge.

Someone else suggested a toffee flavour in BIR curries recently. Another idea of mine was to 'fry' the sugar as part of the cooking process. Now if you boil sugar, you are on the way to making toffee, so that's another thing to try.

Regards
George

I'm prerty sure the 'toffee' flavour comes from pre fried onions; fried slowly until they are soft and slightly coloured. Leave them a while in your fridge, then when you use them in a curry after a few days, thy will impart a 'toffee' type hint.

MarkS has seen curries cooked in his local - we know the ingredients were. He speaks of tablespoons of pre fried onions going in early to the pan. If you follow this method, using soft, sweet onions that have had a bit of time to stand... you'll get toffee. If you use fresh fried ones, you won't.

I use Jaggery.

Jaggery with Tamarind gives sweet and sour like Patia

It looks like a brown golf ball, pkt of about 4-5
only ever seen it in asian outlets.

I've tried mollases more than once, it made no difference, if anything it made it more unlike a BIR curry.
Sorry, I have to give my honest opinion.