Toss cauliflower and sweet potatoes with 2 tablespoons of olive oil, salt and pepper. Place onto a large baking sheet lined with parchment paper and roast in the oven for 30 minutes, or until golden brown and tender. Remove from oven and allow to cool to room temperature.
While the vegetables are roasting you can make the dressing. In a small mixing bowl, add the lemon juice and crushed red pepper flakes. Whisk in the remaining 4 tablespoons of olive oil until incorporated. Season with generous amounts of salt and pepper.
In a large bowl, toss together the arugula with the lemon dressing, cauliflower, and sweet potatoes. Plate the salad, and garnish with prosciutto, toasted pine nuts and shaved parmesan.
Recipe by Oakhurst Kitchen at http://oakhurstkitchen.com/winter-arugula-salad/