In a medium bowl, combine breadcrumbs and milk. Let sit for 5 minutes until softened.
In a large mixing bowl, combine ground beef, ground pork, soaked breadcrumbs, eggs, Parmesan, parsley, garlic, onion, salt, pepper, oregano, and red pepper flakes. Mix gently until combined. Do not overmix.
Scoop about 2 tablespoons of mixture per meatball and roll into balls. Place on a baking sheet. Yields about 24 meatballs.
To fry: Heat 2–3 tablespoons olive oil in a skillet over medium heat. Cook meatballs in batches, turning occasionally, until browned on all sides, about 8–10 minutes. Transfer to a plate.
To bake: Preheat oven to 400°F. Place meatballs on a greased baking sheet and bake 20–25 minutes, until golden and cooked through.
For extra flavor, add cooked meatballs to a pot of marinara sauce and simmer for at least 20 minutes before serving.