Cook spaghetti according to package instructions; drain and set aside.
In a large bowl, combine ground beef, breadcrumbs, Parmesan, egg, garlic, oregano, salt, and pepper.
Mix until well combined, then shape into meatballs (about 1.5 inches in diameter).
Heat a skillet over medium heat and add a bit of oil.
Brown the meatballs on all sides, about 5-7 minutes.
Pour marinara sauce over the meatballs and cover.
Let simmer for 15 minutes, allowing flavors to meld.
Toss cooked spaghetti with a bit of olive oil and season with salt.
Serve spaghetti topped with meatballs and sauce.
Garnish with fresh basil and additional Parmesan if desired.