Boil the lentils for 25–30 minutes, or until tender but firm. Drain and set aside.
Heat a pan and add the olive oil. Fry the peppers, brinjal and onion with the garlic, ginger and chilli until the onion is soft, sweet and translucent and the ginger is fragrant.
Add the cumin seeds and curry, and fry for a further 5 minutes.
Stir through the tomato paste, then add the tomatoes and sugar. Simmer gently for 5 minutes, stirring often. Remove the sauce from the heat, season and stir into the steamed couscous with the lentils.