1. Prepare the matzo balls. In a medium mixing bowl, combine eggs, egg white, oil, onion, garlic, salt, and pepper and whisk until smooth. Add matzo meal and seltzer or soda. Mix to form a thick, wet paste. Stir in parsley if desired. Refrigerate for 1 hour.
2. Fill a large stockpot halfway with water and bring to a boil over high heat. While water heats, gently roll chilled matzo mixture into about 16 to 18 1-inch balls, being careful not to densely pack them. Handle as little as possible. Place on a plate or work surface as you finish each one. When water comes to a boil, drop matzo balls into boiling water. Cover and reduce heat to medium and cook for 30 minutes. Keep covered. Don't peek! They need to steam.
3. While matzo balls cook, prepare the soup. In a second large stockpot, combine broth, carrots, parsnip, and celery. Cover and bring to a boil over high heat, then reduce heat and maintain a simmer until vegetables are tender, about 25 to 30 minutes. Stir in shredded chicken and cook until heated through, another 3 to 4 minutes.
4. To serve, use a large slotted spoon to transfer matzo balls from the pot to 6 bowls, 3 per serving. Ladle chicken soup into each bowl and garnish with a sprig of parsley or chopped chives if desired.
Source: Hannaford fresh Magazine, March - April 2015