Divide meatball mixture into 4/8/12 equal portions (1, 2 or 3 people) and roll them into ball shape. Dust them with a thin layer of flour (any type)(optional).
Add some oil to a pan over medium to high heat, add meatballs in and cook until they are golden brown outside and still a little soft in the middle.Take them out and set aside.
Add onions to the pan, season with a pinch of salt and fry until soft.
Then add in sauce along with meatballs and cook over low heat until meatballs are fully cooked through. (add a little pasta water if the sauce gets too thick)
Step 2: Spaghetti (same time as step 1)
Boil spaghetti in a pan of boiled water until they are soft.