Step 1: Prepare the oven. Preheat it to 375 degrees F. Using a nonstick spray, grease a 9 x 13-inch baking dish and set aside.

Step 2: Place the beef, breadcrumbs, egg, onion, nutmeg, garlic powder, salt, and pepper in a large bowl. Mix well until just combined. Scoop and roll 1 ½ tablespoons of the mixture into a ball. Repeat with the remaining mixture.

Step 3: In a large skillet, heat the olive oil over medium-high heat. To the hot oil, add the meatballs and cook until all sides are browned. Transfer the meatballs to a plate and set aside.

Step 4: In the meantime, cook the noodles in a large pot of salted boiling water for two minutes less than the package directions. Drain and set aside.

Step 5: Add the broth, heavy cream, and Worcestershire sauce to the now-empty skillet, scraping up any delicious browned bits on the bottom of the pan. Allow the mixture to simmer for about 10 minutes until lightly thickened. Season to taste with salt and pepper, then remove the skillet from the heat.

Step 6: Add the pasta into the prepared baking dish and top with the browned meatballs. Evenly pour the cream sauce over the pasta and meatballs, then sprinkle generously with Swiss cheese.

Step 7: Place in the preheated oven and bake for about 20 minutes or until the cheese has melted, browned slightly, and is bubbly. Remove from the oven when done and allow the casserole to sit for about 5 minutes.

Step 8: Garnish with fresh chopped parsley, serve warm, and enjoy!