I would suggest that it should be lighter, the nearest colour I can bring to mind is the colour of a brown manilla envelope. If you cook onions with garlic the garlic will invariably cook the quickest and thus is more likely to bur. If that happens then the base/paste will become bitter.
Have you thought of this approach (which some BIRs around Manchester use)?
Sliced some onions coarsley and deep fry them, but dont burn them. Then use the oil to cook the dish. Crumble in the fried onions towards the end of cooking, e.g. Dhopiazza style.
You can now buy fried onions in bags from a lot of Asian supermarkets, they are not as good as home made but passable. I know that some BIRs use it because that is how I found out this. I think someone else also mentioned you can also buy fried garlic.
CP