Slice apple and fennel thinly on the mandoline.
Gently toss the apple slices with the fennel slices.
Roughly chop the walnuts.
Mix olive oil, apple cider vinegar and honey in a jar and dress the apple and fennel with the mixture. Toss gently again.
Scatter walnuts over the top.
This salad is best served as soon as it is made. Enjoy!