Put the lentils in a large saucepan, cover with cold water and bring to the boil, then simmer for 5 minutes to part cook. Drain and tip into a large mixing bowl.
Heat the oil in a frying pan and gently fry the onion, until softened.
Add the aubergine and cook for a further 5 minutes, until lightly golden.
Add these to the mixing bowl along with the rest of the ingredients and mix.
Transfer the mixture to an oven-proof dish, cover and bake for 50-60 minutes, giving a little stir after 20 minutes.
When everything is cooked, serve hot with a spinach salad.