(You may need to do this in batches.) Transfer the meatballs to a large lidded saucepan. To make the gravy, heat the sunflower oil in the frying pan and gently fry the onion over a low heat for ...
until meatballs are pink in the center when you cut one open and gravy is slightly thickened, 5-7 minutes. Turn heat off and let sit 5 minutes. (The meatballs will continue cooking.) Sprinkle ...