In a large bowl, combine beef, pork, panko, Parmesan, egg, garlic, 1/2 tsp salt, and pepper. Use your hands to mix gently until just combined. Do not overwork or meatballs will be tough.

Roll mixture into 16 meatballs, about 1.5 inches across. Place on a plate and chill in the refrigerator for 10 minutes while you prep the sauce ingredients. This helps them hold their shape.

Heat olive oil in a large skillet over medium-high heat. Add meatballs and cook for 8-10 minutes, turning occasionally, until browned on all sides. They do not need to be cooked through yet. Transfer to a plate.

Reduce heat to medium. Add 2 tbsp butter to the skillet and scrape up any browned bits. Pour in wine and simmer for 2 minutes until reduced by half. Add broth, lemon juice, and capers. Simmer for 3 minutes.

Return meatballs and any juices to the skillet. Cover and simmer gently for 10-12 minutes, turning once, until cooked through and sauce has slightly thickened. An instant-read thermometer should read 160F in the center.

Remove from heat. Swirl in remaining 1 tbsp butter until glossy. Sprinkle with lemon zest and parsley. Serve immediately over buttered egg noodles, mashed potatoes, or with crusty bread to soak up the sauce.