Heat a small frying pan over a medium heat and toast the walnut halves for 3-4 minutes. Leave to cool slightly.
Pull away the outer leaves of each chicory head and divide between plates. Thinly slice the remaining chicory hearts, vertically, and place on top of the whole leaves. Top each plate with a handful of watercress leaves.
Scatter the Roquefort along with the toasted walnut halves over each plate.
Place the cider vinegar, honey and olive oil in a jar and season. Screw the lid on tightly and shake well. Drizzle the dressing over the salad and serve straight away.