Winter Vegetable Soup with Turkish Meatballs

To prepare soup: Heat 3 tablespoons oil in a large stockpot over medium heat. Add leeks, 3 onions and 5 garlic cloves; cook, stirring occasionally, until soft but not brown, about 10 minutes. Add carrots, celery, parsnips, 1 1/2 teaspoons salt and 1 teaspoon pepper; cook, stirring occasionally, for 3 minutes. Stir in potatoes. Increase heat to high and add tomatoes and thyme; cook, stirring occasionally, for 2 minutes. Add broth and bring to a boil. Reduce heat, partially cover and simmer for 20 minutes.

Meanwhile, to prepare meatballs: Heat 2 tablespoons oil in a large skillet over medium heat. Add onion, scallion and garlic; cook, stirring, for 5 minutes. Add 2 tablespoons mint, salt, pepper and 1/2 teaspoon each cinnamon and cumin; cook, stirring, for 1 minute. Scrape into a large bowl and let cool slightly. Wash and dry the pan.

Add beef (and/or lamb), panko, eggs, 2 tablespoons mint and the remaining 1/4 teaspoon each cinnamon and cumin to the onion mixture. Mix until well incorporated. Using a generous 1 tablespoon for each, form into 28 meatballs.

Heat 1 tablespoon oil in the pan over medium-high heat. Reduce heat to medium and add half the meatballs. Cook, turning occasionally, until browned on all sides but not cooked through, 6 to 8 minutes. Transfer to the soup. Repeat with the remaining 1 tablespoon oil and meatballs. Simmer the soup until the meatballs are cooked through, about 15 minutes. Serve the soup topped with yogurt and the remaining 3/4 cup mint.