In a large glass bowl, combine milk and bread crumbs and allow them to soak for 5 minutes.
In a heavy skillet heat extra virgin olive oil over low-medium heat and add onions. Cook until tender. Set aside until needed.
In a large glass bowl, combine onions and soak bread crumbs and allow them to sit for 5 more minutes. With an electric mixer combine whisked eggs, ground chuck, ground pork, nutmeg, allspice and onion/bread crumb mixture. Add salt and pepper to taste. Beat until smooth. Shape into 1 inch balls (weighing about 1 ounce each).
Preheat oven to 400 F. Line a baking sheet with parchment paper and place balls on it and bake for 15 minutes.
Place balls in heavy cast iron fry pan or dutch oven with broth. Cover and simmer on low heat for 2 hours.
When cooked serve on a platter and spoon gravy on top.