For the salad
In a large bowl, mix together the salad ingredients.
For the walnut vinaigrette
In a medium bowl, whisk all the dressing ingredients together by hand.
Taste and adjust the seasoning if necessary.
Dress the salad with the walnut dressing.
Arrange the salad on one side of each plate, leaving room for the soufflé.
Scatter with toasted walnuts and the Saint Agur blue cheese.