How slow can you go?
I used left over lamb on a spit (cooked for about 6-7 hours) and made it into a slow cooked lamb & onion curry.
Frying the whole onions with garlic, fresh chili, chili paste, paprika powder, cumin, coriander. I wanted to use mustard seeds as well, but I had run out so added a dollop of mustard.
I added some water and vinegar and waited for the onions to become more or less soft and the added the lamb (pic below)