Heat the canola oil / sesame oil in a pot over low-medium heat
Add chopped onion, garlic, ginger and cabbage. Stir well and cook for about 3-4 minutes or unil the cabbage becomes soft
Then, add the chopped mushrooms and spring onion and let everything cook for another minute
After about 1 minute add all of the other ingredients (salt, flour, dark soy sauce, apple cider vinegar,brown sugar). Give it a good stir and cook for 5 minutes
Add a bit more salt if needed and start filling your dumplings