In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan cheese, parsley, onion, garlic powder, salt, pepper, nutmeg, and egg. Mix until well combined.
Roll the mixture into small meatballs, about 1 inch in diameter.
In a large skillet, heat the olive oil over medium heat. Add the meatballs in batches, cooking until browned on all sides, about 8-10 minutes. Remove the meatballs and set aside.
In the same skillet, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes until golden.
Gradually whisk in the beef broth, stirring constantly until the mixture thickens. Add the heavy cream and soy sauce, and season with salt and pepper to taste.
Return the meatballs to the skillet, coating them in the gravy. Simmer for an additional 5-10 minutes until heated through.
Serve the meatballs warm, drizzled with gravy, over egg noodles or mashed potatoes.