Start by mixing the breadcrumbs and milk in a bowl. Let it sit for a minute until the breadcrumbs soak up all the liquid. This step is key because it creates a soft base that keeps the meatballs tender. I never skip this because it makes a noticeable difference.
Add the ground beef and pork to a large bowl along with eggs, Parmesan, garlic, parsley, salt, and pepper. Gently add the soaked breadcrumbs. Use your hands and mix just until combined. Overmixing can make the meatballs tough, so stop as soon as everything looks evenly mixed.
Scoop out portions and roll them gently into balls about the size of a golf ball. Try not to pack them too tightly. I usually place them on a tray as I go so they’re ready to cook evenly. Consistent size helps them cook at the same rate.
Heat olive oil in a large skillet over medium heat. Add the meatballs in batches, making sure not to crowd the pan. Brown them on all sides until they develop a nice crust. This step locks in flavor, even though they won’t be fully cooked yet.
Transfer the browned meatballs into warm marinara sauce. Lower the heat and let them simmer gently. This finishes the cooking process and allows the meatballs to absorb the sauce’s flavor. After about 15–20 minutes, they’ll be perfectly cooked and tender.