BRING broth, leeks and chicken to a boil in a large saucepan. Cook over medium-low heat for 15 minutes or until chicken is no longer pink in center. Remove chicken, leaving leeks and broth in pan. Chop chicken into bite-size pieces.
ADD tortellini to pan; boil, stirring occasionally, for 7 minutes.
WHILE tortellini are cooking, whisk eggs, lemon juice, salt and pepper together in a medium bowl. When tortellini are cooked, whisk about 1 cup hot broth into egg mixture. Return egg mixture to soup in pan. Stir in chicken. Serve warm.
