Heat butter in saute pan over medium heat. Add the finely chopped onions, salt, pepper, allspice and nutmeg. Saute for 5 minutes, stirring often. Add the minced garlic and cook for an additional 2 minutes. Turn the heat to low and add the milk. Bring to a simmer.

Place the bread crumbs in a large bowl. Take the onion mixture off the heat and pour over the breadcrumbs. Stir till combined. Mixture will resemble a thick paste. Let mixture cool.

Place beef, pork and eggs in a large bowl. Add the bread crumb mixture and mix until evenly combined. Do not overmix or your meatballs will be tough. Form into 1 1/2 inch balls. I made about 24 meatballs. Refrigerate for 30 minutes.

Heat 3 Tbsp. of olive oil in a large skillet over medium heat. Gently add the meatballs in batches and brown on all sides. Transfer to a large casserole dish or Dutch oven. Preheat oven to 400 degrees.

For the gravy: In the same skillet you used to cook the meatballs melt the 4 Tbsp. butter over medium heat. Add the flour and whisk constantly for 2 minutes until smooth. Whisk in the beef broth and Worcestershire. Bring to a simmer. Add the fresh parsley and the heavy cream. Reduce the heat and continue whisking until the gravy thickens (about 10-15 minutes). Season with the kosher salt and pepper. Pour the gravy over the meatballs in the casserole dish or Dutch oven and bake for 20 minutes. I like to serve over rice pilaf, small noodles or mashed potatoes.