Prepare the apples: In a large mixing bowl, combine the chopped apples, celery, walnuts (if using), and dried cranberries. Gently toss to combine.
Dressing: In a small bowl, whisk together Greek yogurt (or mayonnaise), honey (or maple syrup), and lemon juice until smooth. Taste and adjust seasoning with a little salt, if needed.

Toss: Pour dressing over apple mixture. Toss until all ingredients are well coated with dressing. The lemon juice in the dressing will help keep the apples from browning too quickly.

Chill: While you can serve the salad immediately, chilling it in the refrigerator for about an hour allows the flavors to meld.
To Serve: Give the salad a final toss before serving. Garnish with fresh mint leaves if desired.