In a small bowl, whisk together olive oil, apple cider vinegar, honey, and Dijon mustard. Add salt and pepper to taste. Whisk until well combined and smooth, about 1 minute.

In a large mixing bowl, add mixed greens, diced apples, cranberries, walnuts, and crumbled feta cheese. Gently fold the ingredients together.

Drizzle the prepared dressing over the salad mixture. Gently toss everything until all ingredients are coated.

Transfer the salad to individual plates or a serving bowl. Garnish with additional walnuts or feta if desired. Serve immediately.