In a large mixing bowl, add the spring mix salad greens, shaved carrots, fresh blueberries, thinly sliced red onions, crumbled feta cheese, and coarsely chopped walnuts. Toss gently to ensure everything is evenly distributed.

In a separate bowl, whisk together the champagne vinegar, freshly squeezed orange juice, grated orange zest, honey, Dijon mustard, and a pinch of salt until well blended.

While whisking the vinaigrette, slowly drizzle in the olive oil over a span of 30 seconds to emulsify the dressing.

Drizzle the orange vinaigrette over the salad mixture and gently toss to evenly coat all the ingredients.

Transfer it to a serving platter or bowls and serve immediately.