2 large egg whites
1 large egg
1 tablespoon vegetable oil
1/4 cup unflavored seltzer
2/3 cup matzo meal
2 tablespoons minced parsley
3/4 teaspoon salt (or to taste)
1/4 teaspoon black pepper
6 1/4 cups chicken stock or low-sodium chicken broth
In a medium-size bowl, whisk together the egg whites, egg, and oil, then whisk in the seltzer. Add the matzo meal, 1 tablespoon of the parsley, the salt, and pepper, stirring until smooth. Cover and refrigerate for 30 minutes.
While the matzo mixture chills, half-fill a large saucepan with cold water and bring to a boil over high heat. Using your hands, roll the matzo mixture into 1-inch balls (about 22) and drop them into the boiling water. Lower the heat, cover, and simmer for 40 minutes or just until the matzo balls are cooked through.
In another large saucepan, bring the stock to a boil over high heat, adding additional salt to taste if you wish. Using a slotted spoon, transfer several matzo balls from the boiling water to each soup bowl, then ladle over the hot stock. Garnish with the remaining 1 tablespoon of parsley.