Preheat your oven to 400°F. Line a baking sheet with parchment paper for easy cleanup.
In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan cheese, parsley, garlic, egg, salt, black pepper, oregano, basil, and red pepper flakes. Mix until just combined; do not overmix.
Using your hands, form the mixture into meatballs about 1.5 inches in diameter and place them on the prepared baking sheet, spaced about an inch apart.
Bake in the preheated oven for 20-25 minutes, or until the meatballs are cooked through and browned on the outside.
While the meatballs are baking, heat the marinara sauce in a small saucepan over medium heat.
Once the meatballs are done, remove them from the oven and let them rest for a few minutes. Serve them warm with the marinara sauce on the side or over pasta.