In a large mixing bowl, combine ground beef, ground pork, breadcrumbs, Parmesan cheese, eggs, minced garlic, chopped fresh parsley, dried oregano, salt, black pepper, and optional red pepper flakes. Mix gently using your hands until just combined.

With your hands, scoop about 2 tablespoons of the mixture and roll it into a ball. Place the formed meatballs on a parchment-lined baking sheet.

Heat olive oil in a large skillet over medium heat. Once shimmering, carefully add the meatballs in batches. Cook each meatball for 2-3 minutes on each side until golden-brown. Transfer them to a plate once browned.

In the same skillet, add more olive oil if needed. Sauté the diced onion for 3-4 minutes until softened. Stir in minced garlic and cook for an additional 30 seconds. Add tomato paste and mix well before adding crushed and diced tomatoes.

Sprinkle in dried basil and sugar. Season generously with salt and pepper to taste. Stir and bring the sauce to a gentle simmer for about 5 minutes before adding the browned meatballs back into the skillet.

Reduce heat to low, cover, and allow the meatballs to simmer in the sauce for 25-30 minutes.

Remove from heat and let rest for a few minutes. Serve garnished with fresh parsley and basil, along with extra Parmesan cheese. Pair with crusty bread, pasta, or polenta.