Using about 4 tablespoons of olive oil in a medium sized pan, saute the onions over medium heat until they become translucent. Add the honey and a little more olive oil if the pan looks dry, and cook for 3-5 minutes more. Set aside to cool.
In a large mixing bowl, combine the ground beef with the eggs, breadcrumbs and Worcestershire sauce. and mix well. Then add the sauteed onions plus all the oil from the pan, along with the parsley, basil, garlic powder, paprika, salt, pepper and red pepper flakes if you are using them, and mix thoroughly – by hand is easiest.
Scoop out 18 meatballs: about 2.5 ounces or roughly ice-cream-scoop size, and place them on a rimmed baking sheet or 9×13 pan. Mix the mozzarella, capicola and salami in a mixing bowl. Stuff each meatball by making a hole in the middle and placing 1 tablespoon of the meat-and-cheese mixture in the center. Seal the meatballs well by pinching them back together and roll them together.
Bake, covered with foil, 40 minutes.
Serve with Marinara sauce.
Fabulous with pasta or for meatball sandwiches - or on their own!