1) Evenly divide the salad leaves between 4 plates.
2) Sprinkle with cheese.
3) Right before serving, mix together the cider vinegar, walnut oil, Dijon mustard and seasoning to make the dressing.
4) Pour the dressing all over the salad leaves.
5) Serve the salad slightly chilled or at room temperature. Scatter walnut pieces on top and serve with crusty bread. Best served as an appetizer.