Preheat your oven to 400°F (200°C).

In a large mixing bowl, combine ground beef, breadcrumbs, egg, grated onion, minced garlic, nutmeg, allspice, salt, and pepper. Mix until just combined and shape into 1-inch meatballs. Bake for 18-20 minutes.

Boil a large pot of salted water, add rotini pasta, and cook until al dente (7-9 minutes). Drain and set aside.

In a skillet, melt butter and whisk in flour for 2 minutes. Gradually add beef broth and heavy cream, simmer until slightly thickened (5-7 minutes). Stir in Worcestershire sauce and Parmesan.

In a greased baking dish, mix pasta, meatballs, and sauce until evenly coated. Sprinkle additional Parmesan if desired.

Lower oven temperature to 375°F (190°C) and bake for about 20 minutes until golden and bubbly.

Let the dish rest for a few minutes, garnish with fresh parsley, and serve hot.