I've read many articles here on members getting the fable toffee hit, at various and sometimes unexpected times. There is no doubt that the smell that eminates from a BIR kitchen often bears no resemblence to home.
there is a technique to this that can be replicated at home, by (as you would expect) doing the same as in a BIR kitchen. The 2 magic secrets are heat and movement of the pan.
if you can't get extreme heat at home on your stove, you will find this hard.
If you were to watch the local chef, he will add gravy on top of spices to prevent burning. So as all the spices are cooked, he will have a very high heat and rapidly moved the frying pan back and forth (in a sliding action), on the high gas. Now this has to be done quickly and when the pan is not too full, to prevent slopping on the stove. The action of this will cause flames to engulf the pan. This is fine and is needed. It is at this point that the aroma is released.
Try a dry run with onions, garlic/ginger paste, then a spice mix of your choice (but not dry), add either gravy of 4 tablespoons of water. Remember, movement induces flames, equals toffee aroma. Let me know how you get on.