Scrub your sweet potatoes clean and pat dry. Prick holes all over each potato with a knife. Coat with a light layer of cooking oil and place on a baking sheet in the preheated oven. They should be ready in 45 minutes to an hour, depending on the size of your potato.
Meanwhile, in a pan, heat the remaining tablespoon of oil on medium heat. Fry onion for 8-10 minutes until soft.
Add the minced garlic and cook for a further minute. Then add the cumin seeds and chilli powder for another minute.
Chuck in the tin of tomatoes and tomato puree and bring to the boil. When boiling, reduce to a simmer and leave for 15 minutes to thicken.
When thickened, add in your chickpeas and simmer to heat through for another 10 minutes.
When ready, squeeze the lemon juice in to the mixture along with the chopped coriander.
Halve your baked sweet potato, place on a plate and spoon some of the chickpea tomato mixture. Serve with green veg (I had steamed sprouts, peas, and kale!) and a dollop of plain unsweetened yoghurt if you like.