Wash the mixed salad greens thoroughly under cold running water. Pat them dry and place them in a large serving bowl.

Rinse the fresh blueberries in a colander under cold water. Drain and set aside.

Roughly chop the shelled pistachios and toast them in a dry skillet over medium heat for 3-5 minutes. Sprinkle over the greens.

Crumble the feta cheese and sprinkle it over the salad.

Thinly slice the red onion and add it to the salad. Toss lightly.

In a small bowl, combine olive oil, honey, balsamic vinegar, Dijon mustard, salt, and pepper. Whisk until emulsified.

Pour the dressing over the salad and toss gently to coat.

Taste and adjust seasoning as necessary before serving.

Serve immediately or chill briefly before serving.