Step 1

Heat oven to 400° F (200° C).

Step 2

Whisk the egg yolk in a medium-sized bowl until lightly mixed. Add the Parmesan cheese, parsley, Italian seasoning, salt, garlic powder, and black pepper, and whisk to combine.

Step 3

Add the ground beef to the egg mixture. Use your hands or a large spoon to thoroughly mix the egg mixture into the ground beef.

Step 4

Add the onions and breadcrumbs. Mix them into the meat using your fingers or the spoon.

Step 5

Pour the oil into a small baking dish, swirl to coat the bottom of the dish. Form the ground beef mixture into a large ball and place in the center of the baking dish. Top the meatball with tomato sauce.

Step 6

Place the baking dish in the oven and cook for 20 minutes. (The meatball is done when cooked through, and when it reaches an internal temperature of 165° F on an instant-read thermometer.)

Step 7

Remove from the oven and top with 1 Tablespoon of Parmesan cheese. Cover baking dish with a sheet of aluminum foil and let rest for 10 minutes. Enjoy hot.