Add all of the ingredients for the dressing to a small bowl, whisk until well combined. Set aside.
Assemble the salad
Place the spinach in a large bowl, if serving right away, toss in about a tablespoon of the dressing. If you are preparing this ahead of time, don't add the dressing until right before serving.
Add the sliced apples, pecans and crumbled goats cheese, drizzle on another tablespoon of dressing. Serve with the remaining dressing on the side, so dressing can be added to taste individually.
Notes
Make ahead - although components can be prepared ahead of time such as making the dressing and crumbling the cheese, I don't recommend assembling the salad until just before serving.Leftovers - this salad is best eaten right away, as the dressing will start to wilt the spinach, and the apples will turn brown. If you don't mind that, the salad can be kept in a sealed container in the fridge for about 1 day.