Prepare the Beets: Wash the beets and trim off the tops and roots. Wrap each beet loosely in aluminum foil. Place them on a baking sheet and bake in a preheated oven at 375°F (190°C) for about 45-60 minutes, or until they are easily pierced with a fork. Once done, let them cool until they can be handled, then peel and dice them.
Prepare the Broccoli: Lightly steam the broccoli florets for about 3-5 minutes until they are bright green and tender-crisp. Let them cool.
In a large bowl, combine the diced beets, steamed broccoli, chopped California prunes, red onion, feta cheese, and walnuts.
In a small bowl, whisk together olive oil, apple cider vinegar, Dijon mustard to create the dressing.
Pour the dressing over the salad and toss gently to combine.
Serve chilled or at room temperature. This salad is not only colorful but also packed with nutrients and fiber.