In a small bowl, add all the sauce ingredients and whisk well. Set aside.
In a large bowl, add all the meatball ingredients EXCEPT the scallions and chopped onions. Mix together with your hands and form small equal meatballs.
On a large sheet pan, add the meatballs to one side then the broccoli and chopped onions. Drizzle most of the sauce right on top and bake for about 25 minutes or so.