Heat the oil or ghee in a large, heavy-based pan over a medium heat and cook the onions and cinnamon stick for a few minutes until the onions start to brown. Add the cumin seeds and mix well.

Tip in the squash and continue to cook for a few minutes more, then add the garlic and cook for 1 min. Stir in the chicken and brown for a few minutes, then add the turmeric, ground coriander, chilli powder and tomato purée, stirring to coat the chicken in the spices.

Tip in the lentils and canned tomatoes, swilling out the tomato can with water twice and adding this, too. Season with salt to taste and bring to a simmer.

Add the tamarind to taste, crumble in the fenugreek leaves and stir to combine. Cover and cook for 20 mins more, stirring halfway through.

Uncover and cook for a few minutes more until the curry has reduced to your desired consistency – the longer it cooks, the thicker it will become, as the lentils will break down into the sauce. Squeeze in a splash of lemon juice and sprinkle over the fresh coriander to serve.