1. Fry the onion in the oil until just soft. Next add the vegetables and mix well. Cook over a low heat for 10 minutes. 2. Add the lentils and cook for 2-3 minutes. 3. Dissolve the miso in the vegetable stock. Pour this over the vegetables and add the tomatoes and thyme. Bring to the boil, then simmer, covered, for 1-1 1/2 hours. Season to taste and serve piping hot. NOTES : Lentils make an excellent base for a nourishing soup. Make a meal of this with plenty of wholemeal bread, or serve in smaller portions as a first course. Vary the vegetables according to what is available, but do include some root vegetables which give the mixture a robust quality.