Fry the powder ingredients in little oil and dry grind them. Cook rice. heat 2 tbsp of oil in a pan and season with mustard, channa dal, urad dal, curry leaves and hing. Add groundnuts and fry until golden. Add onions and fry until golden. Add the chopped bell pepper and cook until soft. Cook sweet potatoes separately. Add the cooked sweet potatoes and the ground masala powder. Mix with the fried bell peppers and onions. Stir well. Add 2 tbsp of salt and a pinch of sugar. Mix with the cooked rice and garnish with coriander leaves. Serve hot with onion raitha and papad.