Prepare Meatballs: In a large bowl, combine ground beef, bread crumbs, milk, egg, onion, allspice, and salt. Mix thoroughly, form into 1.5 inch meatballs, and chill for 30 minutes.

Cook Meatballs: Heat olive oil in a skillet, brown the meatballs for 8-10 minutes until cooked through to 165°F, then set aside.

Make Sauce: In the same skillet, sauté onions until translucent, add flour, stir well, gradually whisk in the broth, and cook until thickened for 5-7 minutes.

Combine: Preheat oven to 375°F. Cook pasta until al dente, then combine with sauce and meatballs in a large bowl.

Bake: Transfer to a greased 9x13 inch dish. Optionally sprinkle cheese on top and bake for 25-30 minutes until bubbly and golden.