1. Preheat oven to 375°F and line two baking sheets with parchment paper.

2. In a large bowl, combine ground beef, breadcrumbs, egg, minced garlic, parsley, Parmesan, salt, pepper, and oregano. Mix gently until just combined.

3. Form meat mixture into golf ball-sized spheres and create a deep indentation in each using your thumb. Place on prepared baking sheets.

4. Bake meatballs for 15 minutes until about 80% cooked through.

5. While meatballs bake, heat olive oil in a large saucepan over medium heat. Add diced onions and sauté for 5 minutes until translucent.

6. Add minced garlic and cook for 30 seconds until fragrant.

7. Stir in tomato paste and cook for 2 minutes, stirring constantly.

8. Add crushed tomatoes, beef broth, basil, oregano, and red pepper flakes. Bring to a simmer, then reduce heat to low and cook for 30 minutes.

9. Transfer partially cooked meatballs to the simmering sauce and cook for an additional 15 minutes until meatballs reach 160°F internal temperature.

10. Meanwhile, cook spaghetti in salted boiling water according to package directions until al dente. Drain and toss with olive oil.

11. Pat mozzarella balls dry and press one into the indentation of each meatball. Place a black olive slice in the center of each mozzarella ball.

12. Optional: Use a toothpick dipped in diluted red food coloring to paint veins on the mozzarella eyeballs.

13. Plate pasta in nests or serving bowl, nestle eyeball meatballs throughout, and ladle sauce generously over everything.

14. Let rest for 3-5 minutes before serving to allow flavors to meld.