In a large mixing bowl, combine ground beef, breadcrumbs, milk, and seasonings. Mix until well blended, then shape into meatballs.

In a skillet over medium heat, add meatballs and cook for about 5-7 minutes until browned on all sides.

Remove meatballs and set aside. In the same skillet, sauté chopped onion until translucent, then stir in flour.

Gradually whisk in beef broth and heavy cream, simmer until the sauce thickens.

Boil salted water in a pot. Cook the pasta according to package instructions until al dente, then drain.

In a baking dish, combine pasta, meatballs, and sauce, stirring everything until well coated.

Cover with foil and bake at 350°F (175°C) for 25-30 minutes, removing the foil for the last 5 minutes.

Let cool for a few minutes before serving to meld flavors.