In a large mixing bowl, combine the shredded carrots, diced apples, raisins, and chopped walnuts if using. Toss to mix the ingredients evenly.
In a separate small bowl, whisk together the Greek yogurt, honey, lemon juice, cinnamon, salt, and pepper until smooth.
Pour the dressing over the carrot and apple mixture. Stir well to coat all the ingredients evenly with the dressing.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve chilled as a refreshing side dish or light lunch.