1) Cut courgettes and aubergine into chunks. Sprinkle with salt and leave for 30 minutes.
2) Rinse under cold water and dry with kitchen paper.
3) Slice onions, deseed and slice peppers. Skin and chop tomatoes.
4) Heat oil in a large pan and add aubergine, courgettes, peppers, onions and garlic. Cook for 10 minutes, stirring occasionally.
5) Add the tomatoes, parsley, thyme and seasoning.
6) Stir in tomato purée, cover and simmer over a low heat for 20 minutes.
7) Remove lid and cook for 10-15 minutes to reduce liquid if necessary