You have to try it! I've made a few minor changes to suit our needs, here's the recipe:
2 tbls vegan butter or olive oil
1/2 tsp sea salt
1/4 - 1/2 tsp red chili flakes (depending on how hot you like it)
1 tsp cumin
1 tsp brown sugar (make sure it's not just dyed white sugar like most brown sugars out there!)
4 tbls apple cider vinegar with "mother"
ground black pepper
Heat butter or oil in a pan, add onions and cook until translucent over a medium heat. Add salt, chili flakes and cumin and cook for about 15 minutes. Add remaining ingredients and cook until onions are soft and creamy.