Preheat your oven to 400°F (200°C) and lightly grease a 9x13 inch baking dish. This step helps make cleanup a breeze!
In a large mixing bowl, gently combine the lean ground beef, finely diced yellow onion, long-grain rice, egg, Worcestershire sauce, garlic powder, onion powder, salt, and black pepper. Mix just until everything is combined, being careful not to overmix to ensure your meatballs stay tender.
Roll the mixture into approximately 1-inch meatballs. Aim for consistent sizes so they cook evenly.
In a separate medium bowl, whisk together the tomato sauce, low sodium chicken stock, Italian seasoning, minced garlic, onion powder, salt, and black pepper until it's well combined and fragrant.
Pour half of your delicious tomato sauce into the prepared baking dish. Carefully arrange your shaped meatballs in a single layer over the sauce.
Pour the remaining sauce evenly over the meatballs, making sure they're nicely coated in the savory mixture.
Cover the baking dish tightly with aluminum foil. Bake for 1 hour, or until the rice inside the meatballs is tender and the meatballs are fully cooked through (they should reach an internal temperature of 165°F/74°C).
Carefully remove the dish from the oven. Sprinkle with fresh chopped parsley for a pop of color and flavor, then serve immediately. Enjoy this comforting and wholesome family meal!