Boil the potatoes & cauliflower in a microwave safe bowl with a pinch of salt and turmeric. Heat the oil over medium flame in a large, non-stick kadhai. When the oil is shimmering, add the cumin seed and let it sizzle for about 30 seconds. Add the green chilies, ginger and sauté for another 2-3 minutes. Finally, stir with red pepper powder and turmeric & hing and continue to sauté for another minute or so. Add the potatoes to the kadai and stir well. Cover tightly with a lid, reduce heat to low and cook for about 10-15 minutes. Make sure that the water content is fully absorbed. Sprinkle a pinch of hing and serve hot with roti or bread.