I'd appreciate knowing if anyone is doing this when making base (ie pre frying the onions as a 1st stage).

there are a quite a few existing posts but none give a clear concensus.

i just bung everything in the pot and let it fast simmer and it works spot on. however there are a few things which keep me questioning whether it's a needed or not:

1) i did some onion boiling trials some time ago - this established that browning/caramelising the onion does give an improved flavour (as u'd expect) but not significantly better
2) to carryout this "pre frying" would add to the effort and possibly time in making a base and i'm just not convinced BIR's would do it.
3) the onion paste works well for me and is effectively brown/caramelised onion. am i now making this because the taste is not already in the base ie both methods are good ie boiled base with onion paste or prefried onion and no paste
4) the real BIR base i tasted did not have a caramelised onion taste.

what's the verdict? Yes or No

I think that most BIR's dont brown the onions in the base but will flash fry an onion paste (or finely chopped) at initial stage of cooking the dish itself .. along with garlic/ginger paste .. then add base to that ..
the base is really just a spiced vegetable stock ..

I think you would either need an enormous pan to caramelise all the onions in one go or be prepared to spend an eternity doing them in small batches. If you overcrowd the pan the onions will just stew in their own juices rather than frying/caramelising and so you would end up at square one, with a stewed onion base.
I'd not be inclined to bother, just add onion paste as required.
CoR

I've tried bases both ways: prefrying the onions, and just boiling the lot.

Personally, I haven't noticed a difference that I could say "this way is better". More important is the spice mix/ratio and other veg/oil.

thanks josh, CoR, lightboy

exactly what i believe too. the chef at my local TA say's in similar words exactly as lightboy suggests, "the base is really just a spiced vegetable stock".

the only question left for me is: are there any contrarian base makers out there that are doing anything different (to putting all in a pan and boiling).

a recent post highlighted the post in the link below which i'd not come across before.

for me it's added weight to not browning/caramelising (para 1 under method in Belan's post) - link : https://curry-recipes.co.uk/curry/index.php?topic=1921.msg16664#msg16664