Preheat the oven to 375 degrees. Line a large baking dish with foil and grease with cooking spray.

In a large bowl, combine ground beef, ground pork, oregano, onion, breadcrumbs, eggs, salt and pepper. Bring the mixture together with your hands until well-combined.

In a small bowl, stir together the parmesan, provolone and mozzarella cheeses. Use your hand to press together 1 Tbsp of the cheeses into a small ball. Repeat with the remaining cheese until you have 15 small cheese balls.

Form a large ball with the meat mixture and flatten it into a disk in your hand. Place one small ball of cheese in the center and wrap the meat around it, making sure to tightly seal in the cheese. Place seam side down in the baking dish. Repeat with the remaining meat and cheese balls.

In a large skillet, heat 1 Tbsp olive oil. Sear the meatballs on all sides, then place back into the lined baking dish.

Bake for 15 to 20 minutes, until the meatballs are cooked through.

While the meatballs are baking, combine all ingredients for the sauce in a medium sauce pan. Bring the mixture to a simmer and cook until the meatballs are done.

Serve meatballs with sauce and extra fresh basil and grated parmesan cheese. You may also serve the meatballs with pasta if you wish.