Quarter and core the apple, but do not peel. Cut into paper-thin slices with a mandoline or knife.
Pit and halve the cherries.
Toss the apple slices and cherries with the spinach, hazelnuts, and goat cheese in a large serving bowl.
Whisk the vinegar and mustard together in a small bowl. Whisk in the Carapelli Organic Extra Virgin Olive Oil in a slow stream until it thickens into a vinaigrette. Taste and add salt and pepper as needed.
Toss the vinaigrette with the salad and serve immediately.