To prepare vinaigrette, combine first 6 ingredients in a small bowl, stirring with a whisk. Set aside.
To prepare the salad, cook the parsnip and carrot in 6 cups boiling water for 1 minute or until tender; remove vegetables with a slotted spoon. Add lentils; bring to a boil. Reduce heat, and simmer for 15 minutes or until tender; drain in a colander. Cool.
Combine parsnip, carrot, lentils, celery, onions, and parsley in a bowl; stir in vinaigrette. Marinate at room temperature for at least 20 minutes.