You have to stir it a lot after you add the vinegar or you will get burning. The salt and pepper comes at the end of cooking.
So I have roughly 15lbs. of White Onions because my friends are cheeky cunts
This uses a lot of onions and is quite tasty
panningtheglobe.com
I use a combination of chicken & beef broth and add frozen peas and carrots, because that's how my African neighbor made it
make empanadas. the trick is to use a ration of double the meat. So if you have 1 kilo meat, use 2 kilos onions.
Its super easy and you can make it a ton of different ways. I've made it for many years now at home and even have even put a couple variations on the menu a couple of times.
A good first time is onion jam is a ton of onion julianned and then slowly caramelized, add in some garlic that has been slow roasted whole in the oven and then made into a creamy paste, then add some balsamic vinegar, sherry, port wine, or cognac, and some fresh rosemary. You can can it and store it for quite a while too.