Heat 1 tbsp oil in a frying pan and cook the onion and garlic for a few minutes. Add the chilli powder and mince to the pan and break up, cook for 5 minutes until browned all over, with no pink showing. Stir in the tomatoes, kidney beans and 100ml water. Cook over a medium heat for 15 minutes. Meanwhile peel and chop the sweet potatoes, place in a pan of cold salted water, bring to the boil and cook for about 10 minutes, or until cooked through. Drain, mash and stir in a little chopped coriander. Heat a grill to high. Spoon the hot mince into 4 mini casserole pots, freezing the leftovers. Divide the sweet potato mash between each pot and grill for a few minutes to turn the tops golden before serving. For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.