1. Combine turkey, quinoa, 1/4 cup cheese, parsley, basil, 1/4 teaspoon salt, 1/4 teaspoon black pepper, 2 garlic cloves, and egg in a large bowl; mix gently just until combined. Working with damp hands, shape turkey mixture into 24 meatballs (about 2 tablespoons each).
2. Heat a large Dutch oven over medium-high heat. Add 1 teaspoon oil to pan; swirl to coat. Add 12 meatballs; cook 8 minutes, turning to brown on all sides. Remove from pan. Repeat procedure with 1 teaspoon oil and remaining 12 meatballs. Add remaining 2 teaspoons oil to pan; swirl to coat. Add shallots and celery to pan; sauté 5 minutes. Add remaining 4 garlic cloves; sauté 1 minute. Add kale, remaining 1/2 teaspoon salt, remaining 1/4 teaspoon black pepper, and red pepper; cook 2 minutes, stirring occasionally. Add stock; bring to a boil. Return meatballs to pan. Reduce heat; simmer 10 minutes or until kale is tender and meatballs are done. Ladle 1 1/3 cups soup into each of 6 bowls; divide remaining cheese evenly among bowls. Serve with lemon, if desired.