Walnut And Roquefort Salad

• 3 walnut (halves)
• 1 head romaine
• 1 bunch scallions with tops
• 1/2 head chicory
• 110 gr roquefort cheese
• 100 ml olive oil
• 16 ml wine vinegar (white)
• 1 gr pepper (freshly ground)
• 1 gr salt
• 1 slice avocado