Cook the beets by either roasting or boiling until fork-tender. Allow them to cool before peeling.

In a mason jar or a mixing bowl, combine the dressing ingredients: extra virgin olive oil, Dijon mustard, honey, and freshly squeezed lemon juice. Whisk or shake well until emulsified.

Layer the salad with baby spinach, mandarin oranges, red onion, and toasted pine nuts.

Top each bowl with sliced beets and crumbled feta cheese. Optionally add black pepper.

Serve immediately or refrigerate for up to an hour before serving.