Spinach Salad with Apple and Red onion

1 lb. triple-washed spinach, de-stemmed
a small golden delicious apple, quartered, cored and sliced
1/4 small red onion, thinly sliced
1/4 C. olive oil
1 1/2 T apple cider vinegar
1 t. grain mustard
1 T honey
Coarse salt and black peper

Place spinach, apple and onion in a salad bowl. Place oil, vinegar, mustard and honey in a small plastic container and fit lid on conatiner. Shake dressing to combine, 1 minute. Pour dressing over salad, toss and season with salt and pepper, to taste