Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large bowl, combine the cooled pasta, chopped spinach, cherry tomatoes, feta cheese, dried cranberries, and red onion.

In a small bowl, whisk together the olive oil, balsamic vinegar, garlic powder, salt, and pepper.

Pour the dressing over the pasta salad and toss gently to combine all ingredients evenly.

Chill the salad in the refrigerator for at least 30 minutes before serving to allow the flavors to meld.

Serve cold or at room temperature.