Combine the beef, pork, egg, breadcrumbs, 1 clove garlic, 1/2 the onion, and Italian seasoning in a large bowl. Use your hands to mix everything together, taking care not to overwork the meat. Divide into 12 rounds.
Heat the oil in a large skillet over medium-high heat. Add the meatballs and cook for 3 minutes on each side, or until browned. Transfer to a plate.
Add the remaining onion and garlic to the skillet and cook 2-3 minutes, or until softened. Stir in the wine, if using, and cook until nearly all evaporated, scraping up any browned bits from the bottom of the pan. Whisk in the chicken broth and lemon juice. Add the meatballs and prunes and bring to a simmer. Cook 20 minutes, or until the meatballs are cooked through and the sauce is reduced.
Season to taste with salt and pepper. Stir in the pine nuts and sprinkle with parsley. If desired, serve with yogurt and lemon wedges.