Preheat oven to 425. In a large bowl toss together cauliflower florets and potatoes with olive oil, salt and pepper. Make sure to use enough oil to coat the veggies. Roast for 20-25 minutes or until tender. Remove from oven and let cool slightly. In a serving bowl, layer greens, lentils and roasted vegetables. Drizzle with dressing and top with nuts.