Clean and wash the radicchio, pluck it into bite-sized pieces and drain in a colander.
For the dressing, mix together vinegar, sugar, mustard and a strong pinch of salt and pepper each, then beat in the oil until a creamy salad dressing is formed.
Divide the salad on two plates. Quarter, core and peel the pear, cut into bite-sized pieces and spread over the radicchio. Break the walnut halves into pieces and sprinkle over them. Drizzle the dressing over it. Use a peeler to peel off the chips from the parmesan and spread on the salad.
Fresh baguette and a fruity white wine go well with it.