I made my first Bunjara yesterday but instead of frying the onions to caramelise them I used a slow cooker. This has pros and cons. The obvious con is the time taken, around 9 hours total. That will have some of you falling off your chairs but it wasn't an issue for me as you just leave it to do its thing and stir maybe 3 or 4 times at 2 hour intervals.
The advantage is you can control the caramelisation without fear of burning the onions so you can get them good and dark and sweet. Basic technique I used was to put the chopped onions, oil and cinnamon & bay leaves in the slow cooker. Cook on high for 3 hrs with the lid open a crack (this allows the water to sweat out of the onions), then turn down to low with the lid closed for 5-6 hrs depending on how long it takes. You have full control over how far the onions go and of course you can taste them at your leisure towards the end to see if any bitterness remains.
The final stage is back into the frying pan to fry the cumin in oil, add the ginger/garlic paste and stir round, then put the caramelised onions in the pan with the spices, salt and tomato paste. Give it a good stir then finish with tomato pulp and stir cook for 5 mins. I removed my cinnamon stick after the slow cooker stage.
I'm a total newbie so far be it from me to suggest this is an improvement on the original techique, simply an alternative that people might want to consider. I've attached a photo but it was taken on my phone and the exposure is a bit wrong.