1. Combine first 3 ingredients in a food processor; process until coarsely ground. Combine breadcrumb mixture and milk in a medium bowl; let stand 5 minutes. Add nuts and next 4 ingredients (through liver) to milk mixture. Shape into 12 meatballs, about 1 1/2 tablespoons each.
2. Heat a medium nonstick skillet over medium-high heat. Add oil to pan; swirl to coat. Add meatballs; cook 4 minutes, turning to brown on all sides. Remove meatballs from pan. Wipe pan clean; heat over medium heat. Add Turkey-Saffron Stock and celery to pan; bring to a simmer. Return meatballs to pan in a single layer. Cover and simmer 10 minutes or until meatballs are done. Place 2 meatballs in each of 6 shallow bowls. Ladle about 1/3 cup stock mixture into each bowl.