This fuss-free gratin uses greens such as cauliflower, broccoli, red bell peppers, shiitake mushrooms, carrots, red onions and potatoes. Sprinkle some salt and drizzle olive oil over the mixture. Lastly, spread a generous amount of parmesan cheese on top and put it in an oven to bake. Before serving, sprinkle some sesame seeds and sesame oil for Asian fragrance. This serves well as a main or even a side dish.