Preheat your oven to 400°F.
In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan cheese, parsley, garlic, egg, salt, black pepper, oregano, and red pepper flakes. Mix until just combined; do not overmix.
Form the mixture into meatballs, about 1 to 1.5 inches in diameter.
Place the meatballs on a baking sheet lined with parchment paper. Drizzle with olive oil.
Bake in the preheated oven for 20-25 minutes, or until cooked through and browned.
While the meatballs are baking, heat the marinara sauce in a saucepan over medium heat.
Once the meatballs are done, add them to the sauce and simmer for an additional 5 minutes.
Serve the meatballs with spaghetti, on a sub roll, or on their own with extra sauce.