I normally boil the onions for about 2 hours untill they become mush.The first hour on a high heat,,the last hour on medium ....It's only when you blend and cook further then there is a danger of it burning and sticking to the bottom of the pot.....but with my method,sorry Cafe India method there is no further cooking after the blend...In the past once blended i use to cook for a further 45 minutes but i now add this time before i blend,tasting,making sure it's sweet and sugary and then i know it's ready to blend... Oily curry's are fine for home use but my costumers don't want to see it,,unless you specifically ask for a curry with extra oil, which very rarely happens,infact it doesn't...I'm quite certain tho some guys on here would ask for it that way lol..If i cooki for myself i use the old style bringing the oil back to the top....both ways taste exactly the same,but to be honest i like to feel the oil on my lips...MORE PEOPLE ARE HEALTH CONSCIOUS THAN EVER THESE DAYS...If they can't see oil they think, well it can't really be that bad,,If only they knew The choice is yours...bb1