Add cauliflower; cook for 5 minutes. Drain and set aside. In large heavy-bottomed saucepan, heat oil over medium heat; cook onions, stirring, for 3-4 minutes or until softened. Stir in curry powder, cumin, turmeric, mustard seeds, hot pepper flakes, cinnamon and 1/2 ts salt; cook for 1 minute or until mustard seeds begin to pop. Stir in tomatoes and 1/2 cup water, scraping up brown bits. Bring to boil. Stir in cauliflower, carrots and potatoes. Reduce heat to medium-low; cover and simmer for 5 minutes. Taste and adjust seasoning. Per serving: about 175 calories, 5 g protein, 5 g fat, 32 g carbohydrate high source fibre, good source iron