Gary,
your info is totally spot on. premier league status for sure.
have made about 6 test madras curries (about 200ml).
the 1st was using my normal method (oil in med/hot pan, then base sauce, then spice mix, then just before serve a little garam). i found your sauce to be much better than my normal KD. importantly it did not need the garam which has been a real problem in that in getting a spiced dish i could not get an even spice (something however much i change the garam ended up sticking out and spoiling the overall flavour)
the 2nd was your method (and probably closest to your instructions). the garlic did not brown but did release the rawness smell. i got the "toffee" smell which i prefer to call "choking" as to me the smell is nothing like toffee but very much a desired smell. i don't think i simmered for the 5 mins though and tasters complained that fine chopped garlic was still hard.
3rd go i got the garlic slightly brown and left the choking smell develop a little longer but again failed to let simmer enough to Cook the garlic through. this had the taste of takeaway/restaurant standard.
then i went totally wrong. i make pizza myself and pre cook the garlic to avoid it being hard. this ruined the choking smell. the curries were still good but now clearly dropped a league.
conclusions:
1) i am sold on this and the need for toffee smell as you call it.
2) the garlic must be raw and only cooked on medium heat until rawness smell gone (quite quick).
3) full heat is used to cook the water puree spice mix to get the toffee smell
4) essential to simmer for 5mins to get the garlic to cook through
5) i would not put chilli in the base as this reduces cooking stage flexibility
6) the existence of garam in the base gives good spice at cooking stage without anyone spice overpowering the rest
possible changes not really. i like garlic and i did put 1/4 bulb in the base which i think i would increase next time to a full bulb. still retaining the pinch at cooking stage. i am not sure on the absence of ginger but did not miss it. the only mix i buy is a tandoori masala which i use only for chicken either tikka or coated for use on pizza. i might just try this instead of spic mix to change from madras curry to tikka masala curry.
for info my spice mix is LB's Balti book (2 tsp paprika, 1/2 tsp chilli, 1 tsp salt, 1 1/2 tsp coriander, 1 tsp cumin).
Gary, just one question - would a finer chopped garlic be better ie from a mixer rather than by hand (not puree though as i appreciate this i think would be no good)