1kg sweet potato, peeled and chopped into rough chunks
knob of unsalted butter
1. Preheat oven to 180C fan.
2. Heat the olive oil in a large ovenproof casserole pot over a medium, then fry the onions for a few minutes until softened. Add the garlic, carrots, celery and thyme and cook for 5 more minutes.
3. Stir in the mince, breaking it up with a spoon. Once it has browned add the cinnamon, tomato puree, vegetable stock and red lentils. Cover and simmer for 25 - 30 mins.
4. Meanwhile, prepare the steamer. Bring water to a boil, then reduce to a simmer and steam the sweet potatoes until tender, approximately 15 minutes. Once soft, mash the sweet potato well with a knob of butter.
5. Spread the sweet potato evenly on top of the meat mixture.
6. Place in the oven for 20 minutes.
(If making ahead to freeze, skip step 6 and wrap tightly with clingfilm or tinfoil at this point. When ready to use defrost in fridge overnight and then reheat in the oven at 180C fan for approx 45 minutes until heated through..