Add the breadcrumbs and milk to a large bowl. Stir and let sit for 2–3 minutes until the breadcrumbs have absorbed the milk.

Add the ground beef, ground pork, Parmesan, egg, garlic, parsley, Italian seasoning, salt, pepper, and red pepper flakes. Gently mix with your hands just until everything is combined. Be careful not to overmix.

Roll the mixture into small meatballs, about 3/4–1 inch each. You should get approximately 35–40 mini meatballs.

Heat the olive oil in a large skillet over medium heat. Add the meatballs in a single layer, working in batches if needed. Cook for 2–3 minutes per side, turning as needed, until browned all over.

Continue cooking until the centers reach 160°F, about 8–10 minutes total depending on their size.

Serve these mini meatballs with marinara and pasta, make mini meatball subs, add them to soup, serve them as an appetizer, or eat them straight from the skillet.