In a large mixing bowl, combine the ground beef and optional ground pork with breadcrumbs, grated Parmesan, chopped basil, egg, garlic powder, onion powder, salt, and pepper. Mix until just combined.
Take about a tablespoon of the meat mixture and flatten it in your palm. Place a mozzarella ball in the center and wrap the meat around it, sealing the ball completely. Repeat with the remaining meat mixture and mozzarella to form about 12-15 meatballs.
In a large skillet, heat olive oil over medium heat. Once hot, carefully add the stuffed meatballs, making sure not to overcrowd the pan. Cook for about 8-10 minutes, turning occasionally, until browned on all sides.
In a separate saucepan, gently heat the marinara sauce over low heat.
Once the meatballs are browned, transfer them to the saucepan with marinara sauce and simmer for an additional 10 minutes, allowing the flavors to meld and the cheese to melt a bit inside the meatballs.
Serve the meatballs hot, drizzled with extra pesto if desired, alongside spaghetti or a fresh salad.
Notes
Arrange the meatballs on a large serving plate, garnished with fresh basil leaves and a drizzle of olive oil for an appetizing finish. Serve with a side of garlic bread for a complete meal.