Soak thinly sliced red onion in ice water for about 10 minutes to mellow sharpness. Drain and set aside.

In a large mixing bowl, combine the spinach, sliced apples, soaked red onion, toasted pecans, feta crumbles, and dried cranberries. Toss gently.

In a mason jar, combine vegetable oil, apple cider vinegar, maple syrup, Dijon mustard, garlic powder, salt, and black pepper. Seal and shake vigorously for about 30 seconds.

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

Transfer the salad to a serving bowl or platter and serve immediately.