In a small bowl combine the bread crumbs and milk and let soak for 10 minutes. In a large skillet heat 2 tablespoons of the olive oil and cook onion for 3 minutes, remove from heat and allow to cool.
In a large bowl combine ground meats, soaked bread crumbs, cooked onion, egg, Parmesan,parsley, garlic and salt and pepper and mix well. Shape mixture into 1 1/2-inch diameter balls and set on a plate.
In the same large skillet heat 2 more tablespoons of olive oil and cook the meatballs in 3-4 batches until browned on all sides, about 10 minutes. When meatballs are browned, transfer them to a side plate, add more oil if necessary and continue to cook remaining meatballs.
Add the browned meatballs to the simmering marinara sauce and heat for 10-15 minutes. Serve meatballs and sauce with cooked spaghetti or pasta of choice.
Recipe courtesy of Gourmet Magazine