Using a large wide bottomed pan, fry the onion and carrots in enough olive oil to cover the base of the pan for a few minutes before adding in the mushrooms and pepper as well as the parsley and dried herbs.
When the vegetables are almost soft, add the lentils and 700ml water then bring to the boil and simmer until the lentils are soft. Stir regularly throughout this process.
Season with salt and pepper.
Add the tinned tomatoes and tomato puree and the vegetable stock cube and simmer for a further ten minutes.
Serve with the flatbreads and a large green salad.