Remove the outside leaves from the endives; separate the other leaves and cut them into pieces of around 3 to 4 cm [1 to 1.5 in] into a salad bowl. Roughly crumble the Roquefort cheese into small pieces as well as half of walnut halves. Put both on the endives. 
 Make your vinaigrette: in a bowl mix salt, pepper, and mustard ; slowly add the vinegar and then the oils, always mixing.
 When ready to serve, pour the vinaigrette on the salad, mix the whole together, evenly share out salad among the individual ear-dish and finally share on tops the left walnut halves as well. Decorate with parsley if you wish.