In a large bowl, combine the ground beef, breadcrumbs, beaten egg, grated onion, garlic powder, nutmeg, Kosher salt, and black pepper. Mix until just combined.

Scoop the meat mixture into 1 ½ tablespoon portions and roll into meatballs.

Heat the olive oil in a large skillet over medium-high heat. Add the meatballs and brown them on all sides. Transfer the browned meatballs to a plate and set aside.

Meanwhile, cook the egg noodles in a large pot of salted boiling water for 2 minutes less than the package directions. Drain and set aside.

In the same skillet used for the meatballs, add the beef broth, heavy cream, and Worcestershire sauce. Scrape up the browned bits from the bottom of the pan.

Let the sauce simmer for about 10 minutes, or until lightly thickened. Season with salt and black pepper to taste, then remove from the heat.

Add the cooked egg noodles to the prepared baking dish. Top evenly with the browned meatballs.

Pour the cream sauce evenly over the noodles and meatballs.

Sprinkle the grated Swiss cheese over the top.

Bake for about 20 minutes, or until the cheese is melted, bubbly, and lightly browned.

Remove from the oven and let the casserole rest for about 5 minutes.

Garnish with fresh chopped parsley and serve warm.