Sauté the onion gently in a large non-stick pan until softened (approx. 10 mins) using a little water to stop it from sticking.
Add the garam masala, black onion seeds, turmeric, ginger and garlic and continue to sauté for one minute.
Add the sweet potato and aubergine and cook for 5 minutes, stirring to prevent the vegetables from sticking. You can always add a little more water if required.
Add the chopped tomatoes, plus half a can of water, bring to the boil, then reduce and simmer for 15 – 20 minutes until the vegetable pieces are cooked through but still firm.
Add the drained chickpeas and chopped coriander, taste and adjust the seasoning to your liking with salt and black pepper. Serve with rice or naan.
Notes
Ginger gives the curry warmth, but if you like your food spicy feel free to add finely chopped chilli or chilli flakes to taste.
To freeze, cool and then divide into portions in freezer bags or containers. Defrost overnight in the fridge and reheat in a pan until piping hot. This dish will keep up to 3 months in the freezer.
Black onion seeds may also be known as Nigella seeds.