Thinly slice the onion and chop the garlic and ginger. Dice the carrot, sweet potatoes, and red pepper into small chunks.
Heat a little oil in a large casserole dish or deep pan. Add the onion and fry for 5 minutes, until soft and golden.
Stir in the garlic, ginger and mustard seeds. Cook for 1 minute until fragrant.
Add the diced vegetables along with the ground cumin, coriander, turmeric, garam masala, chilli powder, salt and black pepper. Stir well to coat everything in the spices.
Mix in the tomato purée and red lentils.
Add the chopped tomatoes and enough water to cover the mixture generously.
Add the bay leaf, curry leaves and star anise.
Bring to a boil, then cover, reduce the heat, and simmer for about 20 minutes, until the vegetables and lentils are tender.
Stir in the chopped duck meat and greens. Add a little extra water if needed to reach your preferred consistency.
Simmer for 5–10 minutes, until the greens are wilted and the duck is heated through.
Remove the star anise, bay leaf and curry leaves before serving.
Finish with a squeeze of lime juice and a sprinkle of chopped coriander.
Serve hot with basmati rice or naan bread and your favourite chutney.